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UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT
STATION
30 d REPORT FOR THE FISCAL YEAR
ENDING JUNE 30th, 1917
MAY, 1918
CONTENTS
PAGE
LETTER OF TRANSMITTAL TO GOVERNOR OF FLORIDA ................. ............- 5R
BOARD OF CONTROL, AND STATION STAFF................................... .... 6R
LETTER OF TRANSMIrTAL TO CHAIRMAN BOARD OF CONTROL...................... 7R
REPORT OF DIRECTOR......................... .......... ................... ...... ......... 7R
Animal Industry, 8R; Plant Nutrition, 9R; Entomological Studies,
10R; Citrus Diseases, 10R; Soils and Fertilizers, 12R; Changes in
Staff, 12R; Provision for Branch Station, 13R; Publications, 13R.
REPORT OF AUDITOR.....- ............----... ......... ---..................... .................. 16R
REPORT OF ANIMAL INDUSTRIALIST.............................. ........................ 17R
The Dairy Herd, 17R; Dairy Herd Record, 20R; Experiments Con-
ducted with Herd, 21R; Beef Herd, 26R; Hogs, 27R; Silage Corn,
28R; Flax, 28R; Japanese-Cane Fertilizer Experiment, 28R; Jap-
anese Cane, 32R; Corn Fertilizer Experiment, 33R; Sweet-Potato
Fertilizer Experiment, 33R.
REPORT OF PLANT PHYSIOLOGIST..................................................................... 35R
Injury to Citrus Trees by the Improper Use of Ground Limestone,
35R; Fertilizer Experiment-with Citrus Seedlings, 46R; Field Ex-
periments with Fertilizers, 46R; Influence of Different Ratios of
Phosphoric Acid and Potash in Fertilizers Upon Growth and Fruit
Production in Citrus, 50R; Efficiency of Finely Ground Phosphate
Rock, Stable Manure and Legumes as a Fertilizer for Citrus, 50R.
REPORT OF ENTOMOLOGIST................................- ....................... 52R
Velvet-Bean Caterpillar, 52R; Control of Nematodes, 53R; Impor-
tation of Beneficial Insects, 58R; Insects of the Year, 59R; Notes
on Other Insects, 63R.
REPORT OF PLANT PATHOLOGIST.............. ............................ 66R
Citrus Diseases, 66R; Some Diseases of the Season, 73R; Pecan
Diseases, 75R.
REPORT OF ASSOCIATE PLANT PATHOLOGIST.............................................. 76R
Vegetable Diseases, 76R; Damping Off in the Seed Bed, 76R;
Phomopsis of Eggplant, 77R; Buckeye Rot of Tomato Fruit, 78R;
Bacterial Spot of Pepper, 79R; Pepper Pink Joint, 83R; Other
Diseases of Importance, 84R; Pineapple Wilt, 85R.
REPORT OF LABORATORY ASSISTANT IN PLANT PATHOLOGY........................... 87R
Pecan Dieback, 87R; An Undescribed Gnomonia on Pecan Leaves,
89R.
REPORT OF CHEMIST............. ............. .. .................. ...................95R
Citrus Experimental Grove, 95R; Phosphoric Acid in Grove Soils,
97R; Soil Tank Investigations, 102R.
BULLETIN 132.-Loss OF FERTILIZERS BY LEACHING................................... 1
Plan of Experiment, 3; Composition of Tank Soils, 4; Composition
of Drainage Water from Unfertilized Soil, 5; Loss of Plant Food
from Unfertilized Soil, 6; Loss from Fertilized Soil, 9; Change in
Composition of Soil, 18; Conclusions, 19.
BULLETIN 133.-IRIs POTATOES IN FLORIDA.............................. ......... 21
Soils, 23; Preparation of the Soil, 24; Fertilization, 24; Planting,
26; Seed Potatoes, 27; Causes of Imperfect Stand, 28; Cultiva-
tion, 28; Harvesting, 29; Marketing, 29; Rotation, 29; Irrigation,
30; Frost Protection, 30; Diseases, 31.
BULLETIN 134.-FLORIDA TRUCK AND GARDEN JNSECTS............................... 33
Introduction, 35; Life History of Insects, 36; Indirect Methods of
Combating Insects, 37; Direct Methods, 39; General Garden In-
sects and Pests, 44; Insects Injurious to-Beans, 51; Lima Beans,
56; Beets, 56; Cabbage, 59; Cantaloupes, 71; Carrots, 71; Cauli-
flower, 71; Celery, 71; Corn, 73; Cowpeas, 82; Cucumbers, 85;
Dasheens, 90; Eggplant, 90; Lettuce, 91; Melons, 92; Mustard,
92; Okra, 92; Onions, 94; Parsley, 96; Peas, 96; Peppers, 99;
Potatoes, 99; Radishes, 102; Roselle, 102; Squash, 102; Straw-
berries, 104; Sunflowers, 107; Sweet Potatoes, 108; Tomatoes,
111; Turnips, 121; Watermelons, 12L
Contents
PAGE
BULLETIN 185.-TH~ UTImZATION Or CULL CITU FRaITS IN FLORIDA.. 129
Introduction, 181; Preservation of the Juice, 132; Extraction of
Oil from the Peel, 139; Preparation of Alcohol, 142; Production of
Citric Acid. 148; Utiliation of the Waste Pulp, Seeds and Peel,
143; Conclusions, 143.
BULLETIN 136.-CONTROL Or ROOT-KNoT BY CALCIUM CYANAMID AND
OTHER MEANS............................-................-.....-....... 145
What Is Root-Knot, 147; "Cyanamid," 148; Effect of Cyanamid
on Nematodes in Radish Bed, 148; Experiments with Cowpeas,
149; Experiments in a Greenhouse, 150; Experiments with Winter
Truck, 152; Effect in Plots Not Irrigated, 162; Experiments on
Seed Beds at Sanford, 152; Conclusion, 153; Vermicidal Effect
Not Due to Nitrogen or Lime, 155; Time Between Treatment and
Planting, 156; Cost, 157; Fertilizing Value, 157; Effects on Other
Organisms in the Soil, 168; Where Cyanamid Will Be of Most
Value, 158; Host Plants of Nematodes, 168; Starving the Nema-
todes, 159; Other Methods of Freeing the Soil, 160; Avoid Rein-
festing the Land, 160.
BULLETIN 137.-SOME CASB OF INJURY TO Crrius TREEs APPARENTLY
INDUCED BY GROUND LIMESTONE.......................................... 161
Introduction, 163; Injury to Citrus Trees by Ground Limestone,
164; Pot Experiments with Ground Limestone, 173; Manner of
Ground Limestone Injury, 176; Methods of Prevention, 177; Meth-
ods of Treatment, 178.
BULLETIN 138.-RHODES GRASS.............................. ......... ........ ............ 181
Testing at the Experiment Station, 183; Seed Saving, 185; Yield
of Hay, 186; Regions in Which to Try Rhodes Grass, 187; Time
of Sowing, 187; Preparation of the Soil, 188; Kind of Soil, 188;
Character of the Grass, 188; Composition of Rhodes Grass Hay,
189; Uses for Rhodes Grass, 189; Acknowledgment, 190.
BULLETIN 189.-SOME IMPORTANT DISEASES OF TRUCK CROPS IN FLORIDA 191
Introduction, 198; Materials Used in Control of Truck Diseases,
194; Sprayers, 200; General Measures for Control of Truck Dis-
eases, 201; Diseases of Truck Crops and Their Control, 210; Beans,
211; Cabbage, 223; Cantaloupes and Cucumbers, 226; Cauliflower,
227; Celery, 228; Eggplant, 232; Lettuce, 238; Peas, 240; Pep-
pers, 241; Potatoes, 243; Sweet Potatoes, 258; Tomatoes, 260;
Watermelons, 269.
PRESS BULLETINS
246.-Guava Propagation.
247.-The Air in the Soil.
248.-Host Plants of the Root-Knot
Nematodes.
249.-The Southern Grass Worm, or
Fall Army Worm.
250.-Cottony Cushion Scale.
251.-Hog Raising in Florida.
252.-The Control of Thrips on To-
matoes.
253.-Corn Planting.
254.-Bulletins and Reports on
Hand.
255.-1oselle Mildew.
256.-The Purple Scale.
257.-Preserving Fungus Parasites
of Whitefly.
258.-Irish Potato Seed.
259.-Controlling Cabbage Worms.
260.-Sweet-Potato Root-Weevil.
.261.-The Red Scale.
262.-Citrus Trees Damaged by
Cold.
263.-Care of Citrus Trees After
Freezing Temperatures.
264.-Red Spiders.
265.-Fertilizers for Sweet Potatoes.
266.-Cucumber and Cantaloupe
Downy Mildew.
267.-Tomato Leaf and Fruit Spots.
268.-Stem-End Rot and Scale In-
sects.
269.-Gummosis of Citrus Trees.
270.-Worms in Swine.
271.-Peanut, Velvet-Bean, and Cot-
tonseed Meals for Milk Pro-
duction.
272.-Citrus Scales and Whitefly.
273.-Lettuce Black Rot.
274.-Sweet-Potato Silage.
275.-Bulletins and Reports on
Hand.
276.-Control of Watermelon An-
thracnose.
277.-Bud-Worm, or Corn Ear-
Worm.
INDEX TO REPORT, BULLETINS, AND PRESS BULLETINS.
Hon. Sidney J. Catts,
Tallahassee, Fla.
Governor of Florida,
SnI: I have the honor to transmit herewith the annual report
of the Director of the Florida Agricultural Experiment Station
for the fiscal year ending June 30, 1917.
Respectfully,
JOE L. EARMAN,
Chairman of the Board of Control
BOARD OF CONTROL
JOE L. EARMAN, Chairman, Jacksonville, Fla.
E. L. WARTMANN, Citra, Fla.
T. B. KING, Arcadia, Fla.
J. B. HODGES, Lake City, Fla.
J. T. DIAMOND, Milton, Fla.
BRYAN MACK, Secretary, Tallahassee, Fla.
J. G. KELLUM, Auditor, Tallahassee, Fla.
STATION STAFF
P. H. ROLFS, M.S., Director.
J. M. Scorr, B.S., Animal Industrialist and Vice-Director.
B. F. FLOYD, A.M., Plant Physiologist.
J. R. WATSON, A.M., Entomologist.
H. E. STEVENS, M.S., Plant Pathologist.
C. D. SHERBAKOFF, Ph.D., Associate Plant Pathologist.
S. E. COLLSON, M.S., Chemist.
J. MATZ, B.S., Assistant in Plant Pathology.
F. F. HALMA, B.S., Assistant Horticulturist.
H. L. DOZIER, M.S., Laboratory Assistant in Entomology.
L. D. STADLER, B.S., Assistant in Dairying.
J. E. TURLINGTON, Ph.D., Assistant Agronomist.
O. W. WEAVER, B.S., Editor.
T. VAN HYNING, Librarian.
K. H. GRAHAM, Auditor and Bookkeeper.
E. G. SHAW, Secretary.
L. T. NEILAND, G.F., Farm Foreman.
Report for the Fiscal Year
Ending June 30, 1917
Hon. Joe L. Earman,
Chairman, Board of Control.
SmR: I have the honor to submit herewith my report on the
work and condition of the Agricultural Experiment Station for
the fiscal year ending June 30, 1917; and I request that you
transmit the same, in accordance with the law, to the Governor
of the State of Florida.
Respectfully,
P. H. ROLFS,
Director.
INTRODUCTION
The work of the Florida Agricultural Experiment Station
during the fiscal year ending June 30, 1917, has been carried
along on essentially the same lines as obtained the previous year.
No important changes have been made in carrying out the
work except in the addition of a project on the experimenting
with and study of forage crops. The moneys for this line of
investigation were furnished by the Florida State Live Stock
Association; this Association making the Experiment Station a
gift of $2,500 for the purpose.
A minor change has been made in the agronomy work of the
Experiment Station, by assigning part time on this work to
Dr. J. E. Turlington, Professor of Agronomy in the Agricultural
College. This is intended to relieve the Animal Industrialist
of a portion of the work along agronomy lines. Dr. Turlington
is taking up the work of studying varieties of cotton, field and
hill selection of sweet potatoes, and some detail work on Jap-
anese cane.
The work on the Adams Fund projects remains the same as
in previous years with the exception that the studies of hybrid-
ization of velvet beans have been discontinued. It is intended
to continue seed production of the various varieties of velvet
beans that have been established from the hybridization work.
Florida Agricultural Experiment Station
ANIMAL INDUSTRY
The work in this Department has been going along in prac-
tically the same lines as taken in previous years. In the dairy
herd special stress is laid on the building up of a reasonably
good dairy herd for experimental purposes. Two full-blood,
young Jersey bulls of high-grade breeding have been donated to
the Experiment Station; one by Hon. P. K. Yonge, of Pensacola,
Fla., and the other by Edmund Butler, of Mt. Kisco, N. Y.
In the milk production an interesting line of experiments were
carried out in the use of peanut meal. Cottonseed meal was used
as a principal source of protein as a check against the peanut
meal. Velvet-bean meal was also used in this experiment. The
results showed that the feed cost per gallon of milk was 16.7c
for cottonseed meal, 16.5c for velvet-bean meal, and 15.5c for
peanut meal. One set of tests was run by using sweet-potato
silage in comparison with corn silage. As a result of this test
it appears that milk was produced at a feed cost of 11.95c a
gallon when corn silage was used and 14.11c a gallon when sweet-
potato silage was used.
The fertilizer tests in connection with Japanese cane were
continued. These seem to indicate that stable manure is one of
the most important fertilizers that can be used in the production
of the Japanese-cane crop.
Since 1907 we have been running fertilizer tests on an area of
land divided into eight plots: the first being treated continuously
with applications of dried blood and muriate of potash; the
second with muriate of potash and acid phosphate; the third
with dried blood and acid phosphate; the fourth with sulphate
of ammonia, muriate of potash and acid phosphate; the fifth
with dried blood, muriate of potash and acid phosphate; the
sixth with sulphate of ammonia, sulphate of potash and acid
phosphate; the seventh with dried blood, sulphate of potash and
acid phosphate; and the eighth treated in the same way as the
seventh but with the addition of carbonate of lime at the rate
of two thousand pounds per acre.
In 1914, the Japanese cane deteriorated so seriously that this
crop was discontinued, and in 1915 and 1916 other crops were
planted on this same area to test the effect of withholding certain
elements from this soil. During 1915 and 1916, it was shown
rather definitely that the yield of sweet potatoes was materially
affected by withholding the application of phosphorus; while
affecting the crop adversely this did not reduce it as much as in
Annual Report, 1917
the case of withholding potash. Where the ammonia was with-
held the crop was equal to that where the phosphoric acid was
withheld. In each case the yield was about 20 percent less than
the average yield of the plots receiving a complete fertilizer.
The results of this test would seem to indicate that potash is an
important element which is likely to be deficient in our soils for
sweet-potato production.
PLANT NUTRITION
Frenching or Chlorosis of Citrus Trees.-A report of.experi-
ments conducted in the greenhouse to determine the conditions
under which ground limestone produces injury to citrus trees.
Citrus seedlings were grown in sand and in sandy loam soils
containing from none to 95 percent ground limestone. In one
experiment the soils were fertilized with a complete fertilizer in
which cottonseed meal was the source of ammonia; in the other
sulphate of ammonia was the source of ammonia.
There was a direct relationship in the amount of injury to the
amount of limestone contained in the soil. The amount of injury
was much less in the plants grown in the sandy loam soil. There
was no marked difference between the plants fertilized with the
organic source of ammonia and those fertilized with the mineral
source of ammonia. The plants receiving these fertilizers but
no limestone, showed a considerable amount of frenching or lack
of green color between the veins of the leaves; but they showed
no complete chlorosing of the leaves that characterized the plants
grown in the limestone soils.
The plants receiving neither fertilizer nor limestone showed
neither frenching nor chlorosing.
Fertilizer Experiments with Citrus Seedlings--Pot experi-
ments with citrus seedlings, comparing the efficiency of different
ammonia and phosphoric acid fertilizers used in sandy and sandy
loam soils. An elaboration of similar experiments carried out
during 1913 and 1914.
The results show that the amounts of fertilizer used in the
1913 and 1914 experiments were optimum amounts. The results
of the different years duplicate.
Field Experiments with Fertilizers-Cooperative experiments
are being carried out in citrus groves to determine (1) the in-
fluence of fertilizer treatment upon the coloration of grapefruit
at maturity; (2) the influence of different ratios of phosphoric
acid and potash upon growth and fruit production; (3) methods
Florida Agricultural Experiment Station
of treatment for lime injury to citrus trees; (4) the efficiency
of the raw phosphates as a source of phosphoric acid for citrus
trees under different soil conditions.
ENTOMOLOGICAL STUDIES
The continuance of the work with the velvet-bean caterpillar
indicated that peanuts may be added to the possible food plants
of this insect (Anticarsia gemmatilis). It does not appear, how-
ever, that the peanut is one of the favorite host plants, as it is
likely the caterpillar will attack peanuts only if adjacent to
plants affected. The study of the migration of the velvet-bean
caterpillar indicates that the caterpillars occur in the southern-
most counties of the State as early as the middle of May. In
spite of this fact the caterpillar does not appear to be as de-
structive in the extreme southern counties, or not any more de-
structive, than in the northern counties of the State. In West
Florida and the southern portion of Georgia adjacent to this
region the caterpillar is far less destructive than in the central
portion of the State. Further tests were made in the effort to
control this insect by the use of arsenical poisons. Dusting with
arsenate of lead mixed thoroly with air-slaked lime has proven
effective in the hands of the entomologist.
Studies in nematode control have been continued and the
results obtained by applying cyanamid as a vermicide gave indi-
cations of a practical way of handling this pest in the truck-
growing regions of the State. A bulletin on the subject has been
published as No. 136.
CITRUS DISEASES
Gummosis of citrus has received another rather careful and
extended study during the year. Thru the cooperation of the
Florida State Plant Board it was possible to make an extended
survey of the State as to the location and occurrence of this
disease. Cultures from a number of trees affected with gum-
mosis showed the development of Phomopsis citri and Diplodia
natalensis in many of the tests. Phomopsis citri has occurred
so frequently in these cultures that this fungus is suspected of
having some connection with the disease.
The work of investigating the practicability of controlling
melanose has been continued. A bulletin on the subject shows
that pruning out of the dead wood will largely reduce the amount
of damage done by this fungus, Phomopsis citri.
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Annual Report, 1917
Minor changes have been made in connection with the soil
cultures of citrus canker. This has been done in cooperation
with and at the request of the State Plant Board.
Investigations on the disease known as foot-rot, which in some
respects is quite similar to gummosis, indicate that Phytophthora
terrestris n. sp. was an active agent in at least some of the dis-
eases known under the general name of foot-rot. It is inter-
esting to know that this same species of fungus was isolated by
Dr. C. D. Sherbakoff, Associate Pathologist, from decaying to-
mato fruits. This species of fungus was repeatedly isolated
from cases of foot-rot occurring in twenty-four widely separated
localities of the State. Inoculation with pure cultures gave typ-
ical lesions as ordinarily observed in the grove.
The studies of seed-bed diseases have been continued. Inoc-
ulation and treatment of seed for the prevention of seed-bed
diseases has been carried out to considerable extent. Investiga-
tion shows Rhizoctonia solani as one of the most common disease-
producing fungi occurring in our seed beds, and considerable
experiments in the greenhouse were conducted with a view to
obtaining some definite knowledge and data in regard to the
control and handling of the seed beds.
Investigation into the widely distributed disease of tomato
fruits, popularly known as buckeye rot of tomato, was carried
out at length. The causative agent of this disease was shown
to be Phytophthora terrestris n. sp. This fungus seems to be
very widely distributed in the State and consequently may occur
at almost any point. Infection of tomato fruits occurs only under
extremely humid conditions and when the fruits are in contact
with the soil, or nearly so.
The study of pecan dieback, caused by the fungus Botryo-
sphaeria berengeriana, has been continued, and a considerable
amount of technical data has been collected on this subject. An
area of one hundred acres of pecans at Komoko was set aside in
the spring of 1916 with a view to testing the effect of pruning
out the dead wood. The difficulty of making an absolutely per-
fect piece of work of removing the dead or affected wood renders
the test somewhat difficult, especially when the trees are of large
size or where considerable disease occurs in the tree. The
results have shown clearly that the pruning-out process, if done
thoroly, will do much toward reducing the severity of the disease.
Incidentally, an undescribed species of Gnomonia parasitic on
pecan leaves was discovered.
* 11R
Florida Agricultural Experiment Station
SoIns AND FERTILZEBS
Investigations in regard to leaching, or loss of fertility from
soils due to rains, has been continued and a detailed table show-
ing the results of this work has been prepared. In a general
way these results are correlated very strongly with those of last
year.
During the first week of February, 1917, a very severe low
temperature occurred in the State. 'Observations were made in
the experimental grove where fertilizer tests have been continued
since 1910. The injury to the trees in the grove was of varying
extent. The bloom was nearly all killed and the twigs were
killed back for a short distance. The defoliation was roughly
estimated at about 20 percent. While the general effect of the
freeze on the grove was somewhat uneven, there was no definite
relation established between the fertilizers applied and the ef-
fects of the freeze. This seems to be somewhat contrary to the
general opinion that fertilizers affect trees favorably and un-
favorably. In a general way it may be said that those plots
receiving an excess of fertilizer were more severely injured
than those receiving a normal application. In a general way
it was noticed that anything that tended to weaken the trees
made them more susceptible to cold injury than where conditions
were normal.
A considerable number of soil analyses have been made of
soils where the fertilizer treatment has been continued for the
last eight years. The analyses and results from this grove indi-
cate with some degree of certainty that the phosphates are not
lost from the soil. Those plots on which four times the normal
quantity of phosphorus has been applied gave analyses showing
that the soil was about four times as rich in phosphorus as those
to which a normal amount of phosphorus has been applied. Indi-
cations from the analyses appear to show that the phosphorus
remains in the soil in the form of calcium phosphate and that
it is not combined with iron or alumina as is frequently sup-
posed,-the soil on which this grove stands having a sufficient
quantity of iron present to permit the phosphorus to change to
this compound if it would do so readily.
CHANGES IN STATION STAFF
A number of changes have occurred in the Experiment Station
staff during the present fiscal year. These, however, have been
12R
Annual Report, 1917
unimportant since they did not involve changes among those
having charge of projects.
Mr. H. G. Clayton, M.S., Assistant in Dairying, resigned his
position to take effect September 15, 1916; Mr. M. N. Beeler,
Editor, resigned his position to take effect December 1, 1916;
Mr. S. S. Walker, Associate Chemist, resigned his position to
take effect March 1, 1917. On September 15, 1916, Mr. L. D.
Stadler accepted the position of Assistant in Dairying, and re-
signed the position on June 10, 1917. On July 1, 1917, J. E.
Turlington, Ph.D. (Cornell), Professor of Agronomy, accepted
work part time as Assistant in Agronomy. On December 4,
1916, O. W. Weaver, B.S. (Kansas State Agr. Col.) accepted
the position of Editor.
PROVISION MADE FOR BRANCH STATION
In connection with new laws passed affecting the Experiment
Station, our recent State Legislature, 1917, made a provision
whereby a branch station might be established in Polk County
provided the land and other materials, including money, amount-
ing to $10,000, were donated by local citizens. The following
is the Act:
BE IT ENACTED BY THE LEGISLATURE OF THE STATE
OF FLORIDA:
Section 1. That the Board of Control be authorized and directed to
locate, establish and maintain a Branch Experiment Statiot, in or
near Winter Haven, Polk County, in the citrus-growing section of the
State, where insect pests, diseases and other agencies affecting the
production of citrus fruits and citrus trees shall be studied.
Section 2. That the supervision and direction of the research work
of such a laboratory shall be vested in the Board of Control.
Section 3. That the Board of Control is hereby authorized to accept
donations of lands, groves, moneys, or other things of value that
may be utilized in conducting the aforesaid investigations; provided,
that no branch station shall be established if such lands, groves,
moneys, and other things of value be of less than ten thousand dol-
lars ($10,000) value.
Section 4. That all laws and parts of laws inconsistent herewith
are hereby repealed.
Section 5. That this Act shall go into effect immediately upon its
becoming a law.
PUBLICATIONS
Following is a list of the publications issued by the Experi-
ment Station for the fiscal year ending June 30, 1917.
Bulletin Total
Number Title Edition Pages Pages
132 Loss of Fertilizers by Leaching........-..--.... .. 25,000 20 500,000
133 Irish Potatoes in Florida (revised)................ 20,000 12 240,000
134 Florida Truck and Garden Insects.........---....- 15,137 96 1,453,152
13R
Florida Agricultural Experiment Station
135 The Utilization of Cull Citrus Fruits in Florida 6,361 16 85,776
136 Control of Root-Knot by Calcium Cyanamide
and Other Means..............-.......-........- 15,212 16 243,392
137 Some Cases of Injury to Citrus Trees Appar-
ently Induced by Ground Limestone............ 10,280 20 205,600
138 Rhodes Grass.... ................................................ 15,305 10 153,050
139 Some Important Diseases of Truck Crops in
Florida.................. ...... ---................ ........... 15,000 88 1320,000
Totals. ...... ....... .......................... 121,295 278 4200,970
ANNUAL REPORT, 1915-16, with index to all publica-
tions for the year...................................... 4,000 122 488,000
SUMMARY OF BULLETINS
132. Loss of Fertilizers by Leaching. (Stanley E. Collison and Seth S.
Walker.) Pp. 20, figs. 5. A report of investigations made to determine
the kinds and quantities of plant food lost from Florida soils by leaching.
133. Irish Potatoes in Florida. (Revised.) (A. P. Spencer.) Pp. 12,
figs. 4. A discussion of the Irish potato as grown in Florida; soils, seed,
planting, fertilizing, cultivating, harvesting and marketing; to which is
appended a short statement relative to potato diseases and measures for
their control.
134. Florida Truck and Garden Insects. (J. R. Watson.) Pp. 96, figs.
57. This bulletin describes insects and other animals in Florida truck fields
and gardens; gives an account of their life history and states the best
methods for their control. Formulas for the more common insecticides are
included.
135. The Utilization of Cull Citrus Fruits in Florida. (Seth S. Walker.)
Pp. 16. This bulletin presents a summary of an original monograph by
F. Alex. McDermott, who made a laboratory study of methods for utilizing
cull citrus fruits.
136. Control of Root-Knot by Calcium Cyanamide and Other Means. (J.
R. Watson.) Pp. 16, figs. 1. A discussion of root-knot, its cause, and a
promising method for eradicating the disease from truck fields by the use
of calcium cyanamide. An account of numerous experimental soil treat-
ments is given.
137. Some Cases of Injury to Citrus Trees Apparently Induced by
Ground Limestone. (B. F. Floyd.) Pp. 20, figs. 6. A report of experi-
ments conducted in the greenhouse and in the field to determine the con-
ditions under which ground limestone produces injury to citrus trees thra
frenching of the foliage.
138. Rhodes Grass. (P. H. Rolfs.) Pp. 10, figs. 1. This bulletin re-
ports the results of attempts to grow Rhodes grass in experimental plots
at this Station. The character of the grass, its composition, and the best
methods for culture are discussed.
139. Some Important Diseases of Truck Crops in Florida. (C. D. Sher-
bakoff.) Pp. 88, figs. 38. This bulletin describes the most common fungus
and bacterial diseases of the more important truck crops and recommends
the best methods for their control. Formulas for fungicides are given and
methods for soil sterilization are described.
PRESS BULLETINS
No. Title Date and Author
246 Guava Propagation-..........-----.. ..... ......July 15, 1916, P. H. Rolfs
247 The Air in the Soil..---.........---.....-.....July 22, 1916, B. F. Floyd
248 Host Plants of the Root-Knot Nematodes-.July 29, 1916, J. R. Watson
249 The Southern Grass Worm, or Fall Army
Worm............................. ........... Aug. 5, 1916, J. R. Watson
250 Cottony Cushion Scale ...................................Aug. 12, 1916, J. R. Watson
251 Hog Raising in Florida.............................Aug. 19, 1916, A. P. Spencer
252 The Control of Thrips on Tomatoes........... Aug. 26, 1916, J. R. Watson
253 Corn Planting.-- .....................Sept. 2, 1916, A. P. Spencer.
14R
Annual Report, 1917 15R
254 Bulletins and Reports on Hand for Distribution...............Aug. 1, 1916
255 Roselle Mildew ..S...........................---. .Sept 30, 1916, P. H. Rolfs
256 The Purple Scale ................. ......Oct. 7, 1916, J. R. Watson
257 Preserving Fungus Parasites of Whitefly..-Oct. 28, 1916, J. R. Watson
258 Irish Potato Seed--...........................Nov. 11, 1916, C. D. Sherbakoff
259 Controlling Cabbage Worms ...............Nov. 18, 1916, J. R. Watson
260 Sweet-Potato Root-Weevi...................... Dec. 23, 1916, J. R. Watson
261 The Red Scale......-................................---- Jan. 13, 1917, J. R. Watson
262 Citrus Trees Damaged by Cold................... Feb. 5, 1917, P. H. Rolfs
263 Care of Citrus Trees After Freezing Tem-
peratures .... ........................... Feb. 12, 1917, P. H. Rolfs
264 Red Spiders...... .........................March 17, 1917, J. R. Watson
265 Fertilizers for Sweet Potatoes.................March 31, 1917, J. M. Scott
266 Cucumber and Cantaloupe Downy Mildew
...................... ....... ..Apr. 7, 1917, C. D. Sherbakoff
267 Tomato Leaf and Fruit Spots..................Apr. 9, 1917, C. D. Sherbakof
268 Stem-End Rot and Scale Insects.................Apr. 11, 1917, H. E. Stevens
269 Gummosis of Citrus Trees.........................Apr. 12, 1917, H. E. Stevens
270 Worms in Swine................................................Apr. 13, 1917, J. M. Scott
271 Peanut, Velvet-Bean, and Cottonseed Meal
for Milk Production ..........................Apr. 14, 1917, J. M. Scott
272 Citrus Scales and Whitefly. ..................Apr. 18, 1917, J. R. Watson
273 Lettuce Black Rot. -..............-... .........Apr. 19, 1917, C. D. Sherbakoff
274 Sweet-Potato Silage............... ........-...Apr. 20, 1917, J. M. Scott
275 Bulletins and Reports on Hand for Distribution ..........Apr. 21, 1917
276 Control of Watermelon Anthracnose....-May 12, 1917, H. E. Stevens
277 Bud-Worm, or Corn Ear-Worm..... .-. May 19, 1917, J. R. Watson
16R Florida Agricultural Ezperiment Station
REPORT OF AUDITOR
P. H. Rolfs, Director.
SmI: I respectfully submit the following report of the credits
received and expenditures vouchered out of the funds as speci-
fled:
RECEIPTS
Balance Receipts Total
Adams Fund ............................................... ................ $15,000.00 $15,000.00
Hatch Fund................................ .................-.. 15,000.00 15,000.00
State Experiment................................. $ 121.02 2,500,00 2,621.02
State Repair ............................................... .................. 2,000.00 2,000.00
State Printing.................................. ..... 2,162.75 3,750.00 5,912.75
Sales .................... ................. 16.07 3,604.61 3,620.68
Miscellaneous -........................................... .................. 887.45
$ 2,299.84 $41,854.61 $45,041.90
EXPENDITURES >, uv% tI
Other
Adams Hatch Sources
Salaries .. -........ ....-.. ... .........._... $10,22.46 $ 7,485.00 $ 305.00
Labor ........- ...................... ... 1,170.57 2,931.53 1,789.34
Publications .............. .................. 954.03 3,380.16
Postage and stationery..........---------........ 77.14 748.61 31.18
Freight and express.............................-.....- 158.90 190.61 99.57
Heat, light, etc,-......-- --...............-- -........ 85.65 109.51 44.39
Chemicals and laboratory supplies............... 745.93 110.00 76.49
Seeds, plants, etc..... ..... ...................... ......... 313.12 194.50 166.32
Fertilizers ....................... ............. .... 124.69 27.00 226.70
Feeding stuffs.............. ............... ................ 1,221.78 2,149.05
Library ....................... ... .......... 51.77 291.17 35.90
Tools, machinery, etc..................................... 149.91 165.65 238.36
Furniture and fixtures..... ........---......... 129.38 469.08 550.55
Scientific apparatus and specimens... ..6... 690.64 ................ 216.51
Livestock .- --.. ..-- .... -.................. .......... 983.50
Traveling expenses ............. ...... ..... .... .. ... 784.19 ............... 48.95
Contingent expenses ... -.. .._.- ....... .............__.. 20.00 8.16
Buildings and land......... .--........... 395.65 81.53 1,78.34
Balance..................._....-................ ...... ...... .. 3,313.43
Totals..................................15,000.00 $15,000.00 $15,041.90
Respectfully submitted,
K. H. GRAHAM,
Auditor.
Annual Report, 1917
REPORT OF ANIMAL INDUSTRIALIST
P. H. Rolfs, Director.
SIR: I submit the following report of the Department of
Animal Industry for the fiscal year ending June 30, 1917.
THE DAIRY HERD
One Jersey heifer was purchased during the year, April
Knight's Coomassee No. 339512 by Gamboge's April Knight No.
113643, by Gamboge's Knight No. 95698, out of Golden Rhyme's
Buttercup No. 286574, out of Lady's Golden Rhymer Imp No.
203457.
The following donations were received during the year:
Hon. P. K. Yonge of Pensacola donated the Jersey bull calf
Magnolia Farm Chief No. 153446, dropped Oct. 17, 1916, got by
the Owl's Noble Duke No. 104321, and out of Fern 14th of Hood
Farm No. 285094.
Mr. Edmund Butler of Mt. Kisco, New York, donated the
Jersey bull calf Florida's Majesty No. 153431, dropped December
29, 1916, sired by Reception's You'll Do P. S. No. 5124 H. C.,
he by Gamboge's Knight No. 95698, out of Imported Majesty's
Fairy No. 382300 who was sired by Imported Champion Majesty
No. 93535, and out of Gloria 6th P 11067 H. C. This calf was
imported in dam August, 1916, from the Island of Jersey.
The Jersey bull, Magnolia's Noble Pogis No. 131234, died on
March 9, 1917. Agatha's Gipsy Prince of K. V. F. No. 87041
was sold to Mr. E. B. Greene of Ocala, Florida. The bull, Jewel's
Oxford Lad No. 140602, was sold to C. R. Negus, Viking, Florida.
The following named persons each purchased a purebred Jer-
sey bull calf during the year:
L. C. Prescott, Starke, Florida
J. T. Daniels, Brooksville, Florida
E. J. Gillespie, West Tocoi, Florida
H. G. Lamb, Tallahassee, Florida
F. N. Holmes, St. Augustine, Florida
Harry Owens, Gainesville, Florida
Three grade heifer calves were sold during the year.
During the year, 36 calves were dropped. (Table 1.) Of this
number eight were purebred bulls, four purebred heifers, four-
teen grade bulls and ten grade heifers. All grade bull calves
were sold as veal.
Since the last report seven cows, Nos. 10, 15, 22, 28, 29, 45
17R
TABLE 1.-DAIRY HERD RECORD, JULY 1, 1916, TO JUNE 30, 1917
Cow Number
63.......................
20........................
37..-- -------..
65.. .. ..... .......
15..................
59......-..
21 -......
2 6..........................
35......................
17 ......... .. ...
22 ..........................
25..................
62 ..................-
69 ..............--- -
60....... .............
41..-----........--
24 .........----
36 ---......
57 ---.......
43-.....- ...
50 ...........................
33..-----.....--
52.......... ...-....
42.......- .......
47 .. -... ..
49
1........ ...... .........
342-------- --------
47 --- ----...............
49 .....................
34 6------------------.-
55 --............---- -----
1 ..........................
56 ...... ...............
18..........................
2 0..... ... ... ...
Breed
Grade Jersey
Jersey
Jersey
Grade Jersey
Grade Jersey
Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Jersey
Grade Jersey
Jersey
Jersey
Jersey
Grade Jersey
Grade Jersey
Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Jersey
Jersey
Jersey
Date of
Calving
July 24
Aug. 3
Aug. 11
Aug. 11
Sept. 13
Sept. 15
Sept. 17
Sept. 19
Oct. 14
Oct. 14
Oct. 14
Dec. 8
Dec. 8
Dec. 12
Dec. 17
Dec. 19
Jan. 2
Jan. 22
Jan. 28
Jan. 28
Feb. 1
Feb. 2
Feb. 25
Feb. 26
March 15
March 15
March 20
March 20
April 25, 1917
April 25, 1917
April 30, 1917
May 26, 1917
May 29, 1917
June 3, 1917
June 14, 1917
June 27, 1917
Tattoo
Sire Sex No. in
left ear
............................................. ............ ...................... fem ale 74
female 74
Elberta's Eminent Fox No. 135708 female 75
Agatha's Gipsy Prince of K. V. F. No. 87041: male .
Elberta's Eminent Fox No. 135708 male
Agatha's Gipsy Prince of K. V. F. No. 87041 female 76
Agatha's Gipsy Prince of K. V. F. No. 87041 female 77
Agatha's Gipsy Prince of K. V. F. No. 87041 male
Agatha's Gipsy Prince of K. V. F. No. 87041 female 78
Agatha's Gipsy Prince of K. V. F. No. 87041 female 79
Agatha's Gipsy Prince of K. V. F. No. 87041 male 80
Agatha's Gipsy Prince of K. V. F. No. 87041 male
Magnolia's Noble Pogis No. 131234 female 82
Magnolia's Noble Pogis No. 131234 male
Magnolia's Noble Pogis No. 131234 male
Prince Landseer Tormentor No. 130913 female 83
Magnolia's Noble Pogis No. 131234 female 84
Agatha's Gipsy Prince of K. V. F. No. 87041 male .
Prince Landseer Tormentor No. 130913 male
Prince Landseer Tormentor No. 130913 male
Prince Landseer Tormentor No. 130913 female 85
Agatha's Gipsy Prince of K. V. F. No. 87041 male
Agatha's Gipsy Prince of K. V. F. No. 87041 female 86
Prince Landseer Tormentor No. 130913 male 87
Agatha's Gipsy Prince of K. V. F. No. 87041 male 88
Magnolia's Noble Pogis No. 131234 female 89
Prince Landseer Tormentor No. 130913 female .
Magnolia's Noble Pogis No. 131234 male
Magnolia's Noble Pogis No. 131234 female
Magnolia's Noble Pogis No. 131234 male
Prince Landseer Tormentor No. 130913 male
Prince Landseer Tormentor No. 130913 male
Magnolia's Noble Pogis No. 131234 male
Magnolia's Noble Pogis No. 131234 male
Magnolia's Noble Pogis No. 131234 male 93
Magnolia's Noble Pogis No. 131234 male 94
Magnolia's Noble Pogis No. 131234 male 95
Disposition
Retained in herd
Retained in herd
Sold to L. C. Prescott, Starke
Vealed
Sold
Retained in herd.
Vealed
Sold
Retained in herd
Sold to H. G. Lamb, Tallahassee
Vealed
Sold
Vealed
Vealed
Retained in herd
Retained in herd
Vealed
Vealed
Vealed
Retained in herd
Vealed
Retained in herd
Sold to E. J. Gillespie, West Tocoi
Sold to J. T. Daniel, Brooksville
Retained in herd
Dead when found
Sold to F. N. Holmes, St. Augustine
Retained in herd
Vealed
Vealed
Vealed
Vealed
Vealed
Sold to Harry Owens, Gainesville
Retained in herd
TABLE 2.-HERD RECORD JULY 1, 1916, TO JUNE 30, 1917
M* 0 0
5719.4 5.9 337.44 157.47 665.0 212.80 66.80 146.00 10.0 5.5
18o........ 4853 .0 5.1 247.50 115.50 564.3 180.58 65.88 114.70 11.6 6.3
20........ 4688.5 4.7 220.36 102.83 545.1 174.43 78.75 95.68 14.4 6.1
24 ........ 4221.0 4.4 185.72 86.67 490.8 157.06 59.00 98.06 12.0 6.9
........ 4 .6 5.2 2 .8 10 4 15 8 1.4 7.9
1 ........ 2922.6 5.6 163.67 $ 76.38 339.8 $108.74 $34.99 $73.75 10.2 7.7
7........ 4595.1 5.6 257.33 120.08 54.3 170.98 63.37 107.61 11.8 6.6
9.... 5719.4 .9 337.44 157.47 665.0 212.80 66.80 146.00 10.0 5.5
17........ 3210.5 4.7 150.89 70.42 373.3 119.46 67.97 51.49 18.2 8.5
18........ 4853.0 5.1 247.50 115.50 564.3 180.58 65.88 114.70 11.6 6.3
20........ 4688.5 4.7 220.36 102.83 545.1 174.43 78.75 95.68 14.4 6.1
21........ 5410.1 4.2 227.22 106.04 629.0 201.28 63.51 137.77 10.1 5.6
24..... 4221.0 4.4 185.72 86.67 490.8 157.06 59.00 98.06 12.0 6.9
2549 4151.6 5.2 215.88 100.74 482.7 154.46 64.86 89.60 13.4 7.9
26 4265.6 5.2 221.81 103.51 496.0 158.72 76.53 82.19 15.4 7.9
31........ 2985.1 5.2 15523 72.44 347.0 111.04 42.07 68.97 12.1 7.9
33....... 1676.2 4.8 80.46 37.55 194.9 62.37 37.73 24.64 19.3 9.0
34....... 1863.9 6.0 111.83 52.19 216.7 69.34 38.03 31.31 17.5 11.9
35 3542.6 5.0 177.13 82.66 411.9 131.81 65.71 66.10 15.9 7.3
36........2815.5 4.3 121.07 56.50 327.3 107.74 38.03 66.71 11.6 5.4
37........ 3589.6 5.5 197.43 92.13 417.3 133.54 69.48 64.06 16.6 9.2
41........ 5528.9 5.0 276.45 129.01 642.8 205.70 70.54 135.16 10.9 6.2
42........ 62529.7 3.4 86.01 40.14 294.1 94.11 22.60 71.51 7.9 4.2
47........ 1666.0 4.1 68.31 31.88 193.7 61.98 22.99 38.99 11.8 5.8
49.... 1571.5 4.5 70.72 33.00 182.7 58.46 22.50 35.96 12.3 6.1
50 ....... 2031.6 4.9 99.55 46.46 236.2 75.58 37.24 38.34 15.7 7.4
52 ....... 1642.2 4.2 68.97 32.18 190.9 61.09 22.37 38.72 11.7 6.5
53 1363.0 4.4 59.97 27.98 158.4 50.69 23.36 27.33 14.7 8.5
55 505.2 4.0 20.21 9.43 58.7 18.78 10.62 8.16 18.0 9.4
57 1518.9 5.2 78.98 36.86 176.6 56.51 37.73 18.78 21.3 9.9
59..--- 6676.2 4.8. 320.46 149.55 776.3 248.42 83.77 164.65 10.7 4.8
60 5141.7 4.0 205.67 95.98 597.8 191.30 55.83 135.47 9.3 5.2
61..-- 6074.2 4.1 249.04 116.22 706.3 226.02 71.43 154.59 10.1 5.2
62 5045.8 5.1 257.34 120.09 586.7 187.74 65.76 121.98 11.2 6.3
69 5181.5 4.4 227.99 106.39 602.5 192.80 77.34 115.46 12.8 6.4
54. 334.3 4.6 15.38 7.18 38.8 12.42 6.70 5.72 17.2 7.2
15 2899.1 4.9 142.06 66.29 337.1 107.87 46.25 61.62 13.7 9.5
+ :
0-
17.9
18.4
15.5
26.7
17.9
20.5
15.7
18.9
21.3
23.3
20.0
28.3
29.4
23.2
17.0
25.8
17.1
12.1
17.6
18.4
23.1
18.2
23.2
27.4
31.2
15.5
14.5
15.3
17.5
19.2
24.4
23.2
0
09
14.1
13.6
16.5
4.3
14.1
11.5
16.3
13.1
10.7
8.7
12.0
3.7
2.6
8.8
15.0 0
6.2 "
16.9
19.9
14.4 N
13.6
8.9
13.8
8.8
4.6
.8
16.5
17.5
10.7
14.5
12.8
7.6 c
8.8
Florida Agricultural Experiment Station
TABLE 3.-AGE AND BaEED OF Cows, AND TIME IN MILK
9
9
9
8
6
6
6
6
5
5
5
4
3
4
5
4
3
5
4
3
3
3
3
9
2
2
S2
2
2
2
2
2
2
Breed
Grade Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Jersey
Jersey
Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Jersey
Grade Jersey
Jersey
Grade Jersey
Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Jersey
Grade Jersey
Grade Jersey
Grade Jersey
Jersey
Grade Jersey
SGrade Jersey
Grade Jersey
Jersey
SGrade Jersey
Grade Jersey
Grade Jersey
Date when
Freshened
April 30, 1917
May 29, 1917
Sept. 13, 1916
Oct. 14, 1916
June 14, 1917
Aug. 3, 1916
Sept. 17, 1916
Jan. 2, 1917
Dec. 8, 1916
Sept. 19, 1916
Feb. 25, 1917
April 25, 1917
Aug. 11, 1916
Dec. 19, 1916
Sept. 15, 1916
Dec. 17, 1916
May 26, 1917
Dec. 8, 1916
Dec. 12, 1916
Feb. 2, 1917
Oct. 14, 1916
Jan. 22, 1917
March 15, 1917
March 20, 1917
March 20. 1917
Feb. 1. 1917
March 15, 1917
Feb. 26, 1917
April 25, 1917
Jan. 28, 1917
June 1. 1917
z.
213
287
298
197
258
292
271
291
275
311
317
222
209
311
324
304
256
302
303
317
143
246
143
101
91
91
142
102
110
45
143
30
and 65 were sold. These
the herd.
were the poorest milk producers in
The total number of cattle in the herd is 57, of which 22 are
purebred Jerseys; 18 of these are females, 11 of which had calves
during the year, and 4 are bulls.
DAIRY HERD RECORD
Table 1, page 18R, shows the herd number, breed, date of
calving, sire of calf, sex, tattoo number, and disposition of all
calves dropped from July 1, 1916, to June 30, 1917.
Table 2 shows the year's results in detail. Reference to the
table will give the number of pounds of milk each cow produced
during the year. The important point to consider in this table is
20R
Date when
Dried up
Dec. 30, 1916
March 31, 1917
May 22, 1917
April 3, 1917
June 29, 1917
July 24, 1917
May 10, 1917
July 23, 1916
May 29, 1917
July 10, 1916
Oct. 16, 1916
Oct. 27, 1916
Aug. 6, 1916
Oct. 16, 1916
Feb. 6, 1917
June 30, 1917
Nov. 29, 1916
Aug. 30, 1916
Sept. 16, 1916
March 31, 1917
Oct. 16, 1916
Nov. 18. 1916
Annual Report, 1917
the amount of milk produced, percentage of butter fat, value of
the butter, value of the milk, cost of the feed, feed cost of a gallon
of milk, labor cost of a gallon of milk, total feed and labor cost
of a gallon, and the profit per gallon when milk is worth 32 cents
a gallon.
This table shows a great variation with different individual
cows in the amount of milk produced, and feed and labor cost
of producing a gallon of milk. It also shows a great variation
in the profits obtained from different cows in the herd. For
instance, cow No. 59 produced 6676.2 pounds of milk during
the year while cow No. 17 produced only 3210.5 pounds, a dif-
ference of 108 percent. Cow No. 31 produced even less milk
than did cow No. 17. Other good producers were No. 61, No. 9,
No. 41, No. 21, No. 60, No. 69, and No. 62.
EXPERIMENTS CONDUCTED WITH HERD
COMPARISON OF COTTONSEED MEAL, PEANUT MEAL AND
VELVET-BEAN MEAL FOR MILK PRODUCTION
This test began November 11, 1916, and closed January 17,
1917. The test was divided into three periods of twenty days
each with four days between the periods. The four days between
periods were for the purpose of changing feeds.
During the first period each cow in lot I was given the follow-
ing ration: Cottonseed meal, 3 pounds; wheat bran, 9 pounds;
corn silage, 12 pounds. Lot II, peanut meal, 4 pounds; wheat
bran, 9 pounds; and corn silage, 12 pounds. Lot III, velvet-bean
meal, 6 pounds; wheat bran, 9 pounds; and corn silage, 12
pounds.
During the second period the cows in lot I were fed peanut
meal, lot II velvet-bean meal and lot III cottonseed meal. During
the third period cows in lot I were fed velvet-bean meal, lot I
cottonseed meal, and lot III peanut meal.
PRICE OF FEEDS
The feeds used in this test cost delivered at the barn: Cotton-
seed meal, $50; bran, $40; peanut meal, $40; velvet-bean meal,
$32; and silage, $4 a ton.
RESULTS
The ration containing 540 pounds cottonseed meal produced
301.4 gallons of milk at a feed cost of 16.7 cents a gallon.
The ration containing 720 pounds of peanut meal produced
327.7 gallons of milk at a feed cost of 15.5 cents a gallon.
21R
Florida Agricultural Experiment Station
The ration containing 1080 pounds of velvet-bean meal pro-
duced 327.7 gallons of milk at a feed cost of 16.5 cents a gallon.
The following tables show the detailed results:
TABLE 4.-FEEDS CONSUMED AND MILK PRODUCED
First period, November 11 to 30, 1916.
LOT I Pounds LOT II Poundsal LOT I Pounds
Cottonseed meal.....180.0 Peanut Meal......... 240.0:Velvet-bean meaL...860.0
Wheat bran............540.0 Wheat bran............ 540.0 Wheat bran..............540.0
Sorghum silage ....720.0Sorghum silage .... 720.O'Sorghum silage..... 720.0
Milk produced.........902.S5Milk produced........1044.0 Milk produced..........889.7
Second period, December 5 to 24, 1916.
Peanut meal...........240.0 Velvet-bean meal. 860.0 Cottonseed meaL.....180.0
Wheat bran...........540.0 Wheat bran............ 540.0 Wheat bran- ..........540.0
Corn silage ............720.0 Corn silage .......... 720.0 Corn silage ..............720.0
Milk produced. ........995.6 Milk produced........1048.5 Milk produced..........834.2
Third period, December 29 to January 17, 1917.
Velvet-bean meal.. 360.0 Cottonseed mea .....180.0 Peanut meal-.........240.0
Wheat bran............540.0 Wheat bran..........40.0 Wheat bran..............40.0
Corn silage ......-..720.0 Corn silage.............720.0 Corn silage. .........720.0
Milk produced.......880.2Milk produced........856.1Milk produced........ 715.7
On the average: 180 Ibs. of cottonseed meal with 540 lb. of bran and
720 Ibs. of silage produced............ ...................864.2
240 lbs. of peanut meal, with same produced......... ......... 918.4
860 lbs. of velvet-bean meal with same produced......-....99.5
TABLE 5.-DAILY RATION PEB HEAD Foa EACH LOT
Feeds Pounds Feeds Pounds Feeds Pounds
Cottonseed meaL...-...... 3 Peanut meal.................. 4 Velvet-bean meal.......... 6
Wheat bran................ 9 Wheat bran................. 9 Wheat bran ............ 9
Silage ........ ....... 12 Silage ..........................12 Silage ........................ 12
TABLE 6.-FEED CosT Pn GALLON OF MILK
Cows fed cottonseed meal.
540 Ibs. cottonseed meal @ $50 a ton.....................................$13.0
1620 Ibs. wheat bran @ $40 a ton......................... ..... 32.40
2160 lbs. silage @ $ 4 a ton........................... ....... 4 2
Total cost of feed................. ................... ................. ... $50.22
Milk produced, 301.4 gallons. Cost per gallon.......................$0.167
Cows fed peanut meal.
720 lbs. peanut meal @ $40 a ton................... ................ ..$14.40
1620 Ibs. wheat bran @ $40 a ton................................ 32.40
2160 Ibs. silage @ $ 4 a ton .................. .......... 4.82
Total cost of feed...........................................................................$51.12
Milk produced, 327.7 gallons. Cost per gallon...........................$0.155
Cows fed velvet-bean meal
1080 lbs. velvet-bean meal @ $32 a ton.................................... ...$17.28
1620 lbs. wheat bran @ $40 a ton................................. 32.40
2160 lbs. silage @ $ 4 a ton........................... 4.82
Total cost of feed....................... ....... ..........$.4.00
Milk produced, 327.7 gallons. Cost per gallon.........................$0.165
22R
Annual Report, 1917 23R
TABLE 7.-WEIGHTS OF Cows
November 30, 1916, end of first period.
Lot I Lot II Lot III
Cow Pounds Cow Pounds Cow Pounds
No. 9 ..........................863 No. 21 ..........................777 No. 26 .........................701
No. 17 ......................753 No. 7 ........................858 No. 61 ... .... ..........808
Lavender .... .............790 No. 35 ........................630 No. 37 ............. ..........803
December 24, 1916, end of the second period.
No. 9 ........................858 No. 21 ................... 777 No. 26 ..........................718
No. 17 ............ ..........753 No. 7 .........................860 No. 61 .........................803
Lavender ................755 No. 35 .......... ............628 No. 37 .........................802
January 17, 1917, end of the third period.
No. 9 .... .........867 No. 21 ....... ................ 795 No. 26 .........................695
No. 17 ................. ......718 No. 7 .... ..-........ 832 No. 61 .. .. ....... 802
Lavender .................758 No. 35 ....... ............ 765 No. 27 ................... 808
The weights at the end of the first period and the end of the second
period were taken as equal to the weights at the beginning of the following
period.
CORN SILAGE vs. SWEET-POTATO SILAGE FOR MILK PRODUC-
TION.
This test began February 22, 1917, and closed May 8, 1917.
The fourteen cows used in the test were divided into two lots of
seven cows each. The test was divided into four periods of
sixteen days each with four days between periods for the pur-
pose of changing feeds.
During the first period each cow in lot I was given the fol-
lowing daily ration: Wheat bran, 7.5 pounds; cottonseed meal,
2.5 pounds; and corn silage, 14 pounds. Each cow in lot II re-
ceived wheat bran, 7.5 pounds; cottonseed meal, 2.5 pounds, and
sweet-potato silage, 10 pounds. During the second period the
feeds were reversed; that is, the cows in lot I were given the
feeds that lot II had received, and those in lot II were given the
feeds that lot I had received. During the third period each lot
of cows received the same feeds as used during the first period.
During the fourth period each lot of cows received the same feeds
as used during the second period.
RESULTS
During the experiment the cows fed corn silage produced 917.3
gallons of milk. During the same time the cows fed sweet-potato
silage produced 883.5 gallons of milk, or a difference of 33.8
gallons in favor of the corn-silage ration.
Florida Agricultural Ezperiment Station
FyM COST
In this experiment the feed cost of a gallon of milk was, with
corn silage, 11.8 cents, with sweet-potato silage 14.2 cents. This
difference in cost of production is due entirely to the difference
in the price charged for the two kinds of silage. If the sweet-
potato silage had been charged at the same price as the corn
silage, there would have been practically no difference in the
feed cost of a gallon of milk.
ANALYSIS OF SILAGE
The analysis of sweet-potato silage, as made by the State
Chemist, is moisture, 54.87 percent; crude protein, 1.82; nitro-
gen-free extract, 39.41; fiber, 1.48; fat, 0.66; and ash, 1.85 per-
cent. Silage made from well matured corn analyzes as follows:
Moisture, 73.7 percent; crude protein, 2.1; nitrogen-free extract,
15.4; fiber, 6.3; fat, 0.8; and ash, 1.7 percent.
Comparing the analyses of sweet-potato silage and corn silage
it is evident that there is little difference in the feeding value.
Experience in feeding these two silages has been that 100 pounds
of sweet-potato silage will replace from 150 to 200 pounds of
corn silage in the ration. This, no doubt, is due to the fact that
the sweet-potato silage contains less water and two and a half
times as much nitrogen-free extract as the corn silage.
The cows seemed to relish the sweet-potato silage as much as
they did the corn silage. Both silages kept well in the silo, hence
were in first-class condition when fed.
Silage is not a new feed for dairy cows, but very few feeding
experiments have been conducted with sweet-potato silage.
Those who grow sweet potatoes for feeding purposes will find
that there is little or no loss in storage when they are put in
the silo.
The following tables show the detailed results:
24R
Annual Report, 1917 25R
TABLE 8.-FEDS CONSUMED AND MILK PRODUCED
First period, February 22 to March 9, 1917.
LoT I Pounds LOT 1I Pounds
Cottonseed meal...................... 280.0 Cottonseed meal-...---.-...--- 280.0
Wheat bran........................... 840.0 Wheat bran...---..--.....---. 840.0
Corn silage...............................1568.0 Sweet-potato silage ......- .-1120.0
Milk produced --. -.......... ----2024.9 Milk produced....----------...............2085.7
Second period-March 14-29, 1917.
Cottonseed meaL................... 280.0 Cottonseed meal........................ 280.0
W heat bran ... ..... .............. 840.0 W heat bran........ ..................... 840.0
Sweet-potato silage................1120.0 Corn silage ................................1568.0
Milk produced -........................1938.5 Milk produced.............................2192.1
Third period-April 3-18, 1917.
Cottonseed meal........................ 280.0 Cottonseed meal.......-----................ 280.0
Wheat bran.. ..................... 840.0 Wheat bran.............. ........ 840.0
Corn silage................................ 1568.0 Sweet-potato silage ................1120.0
Milk produced ......................1690.3 Milk produced........................1932.1
Fourth period-April 23-May 8, 1917.
Cottonseed meaL .-............-- 280.0 Cottonseed meal......-------........ -- 280.0
Wheat bran -... -.......-- ...... 840.0 Wheat bran-. ..................------ 840.0
Sweet-potato silage .-.....-......1120.0 Corn silage .-.............-....1568.0
Milk produced ................1659.5 Milk produced-.............. .1843.5
Pounds milk
On the average: 280 lbs. cottonseed meal, 840 lbs. wheat
bran, and 1,568 lbs. corn silage produced-......-... 1937.7
280 lbs. cottonseed meal, 840 lbs. wheat bran, and
1,120 lbs. sweet-potato silage produced..... .......... 1903.9
Feeds
TABLE 9.-DAmRY RATION PER HEAD FOR EACH LOT
Pounds Feeds
Pounds
Cottonseed meal.......................... 2.5
Wheat bran................................ 7.5
Corn silage...-............------..--..... 14.0
Cottonseed meal ...................-------- 2.5
Wheat bran....... .-.....-.............. 7.5
Sweet-potato silage....... .......... 10.0
TABLE 10.-FEED COST PEr GALLON OF MILK
Cows fed corn silage.
1120 Ibs. cottonseed meal @ $50 per ton ................................$28.00
3360 lbs. wheat bran @ $40 per ton.. .....--...........-........... 6720
6272 Ibs. corn silage @ $ 4 per ton .--.. --......--........ -...... 12.54
Total cost of feed...------ --................. ............. ... $107.74
Milk produced, 901.25 gallons. Cost per gallon..-.........---... .$0.1195
Cows fed sweet-potato silage.
1120 Ibs. cottonseed meal @ $50 per ton .... ..........................$28.00
3360 lbs. wheat bran @ $40 per ton.....-.-- ................---- 6720
4480 Ibs. sweet-potato silage @ $13.33 per ton ...........-....... ........ 29.87
Total cost of feed ...................................-------------------......$125.07
Milk produced, 885.5 gallons. Cost per gallon....... ..............$0.1411
26R
Florida Agricultural Experiment Station
TABLE 11.-WaoHrs or Cows
February 22, 1917, beginning of first period.
LOT I Pounds LOT II Pounds
Cow No. 21....... ......................758 Cow No. 17............................68
Cow No. 25...................................578 Cow No. 24....................................665
Cow No. 33....... ........................620 Cow No. 26.... ............................ 688
Cow No. 57........................ .....5.88 Cow No. 36.................... ...... .......75
Cow No. 62 ...............................605 Cow No. 41 .................. ....... ..._710
Cow No. 69 ......... .....................780 Cow No. 50 ...... ......................... 550
Flagler ... .....................................498 Cow N o. 60 .................... ...............670
March 9, 1917, end of first period.
Cow No. 21..................................748
Cow No. 25 ........................... ..... 587
Cow No. 33...................................635
Cow No. 57................................... 608
Cow No. 62............................. .. 613
Cow No. 69 ... ... ...... 741
Flagler ........................................ 510
SCow No.
Cow No.
Cow No.
Cow No.
Cow No.
Cow No.
Cow No.
17 ......................................710
24... ....... ...........................678
26................. ........- 702
36.. .............................. 582
41 ........................ ........706
50 ... .. ......................... 540
60... ......................... -.688
60..-. ..........~... --. -- ...688~gg
March 29, 1917, end of second period.
Cow No. 21........ ........................732 Cow No. 17......................................728
Cow No. 26....................................589 Cow No. 24........ .. ................683
Cow No. 33 ...............................668 Cow No. 26.....................................723
Cow No. 57 ..... ...................622 Cow No. 36........... ...........606
Cow No. 62........ .......................... 620 Cow No. 41......................... ..........727
Cow No. 69..... .........................728 Cow No. 50................ ........... 577
Flagler .......................................... 09 Cow No. 60....................................707
Cow No. 21........
Cow No. 25..............
Cow No. 33..............
Cow No. 57....... ...
Cow No. 62..............
Cow No. 69...........
Flagler ............
April 18, 1917, end of third period.
..................725 Cow No. 17........
....................608 Cow No. 24... .....
......................682 Cow No. 26... .....
.....................652 Cow No. 36......
......................655 Cow No. 41.......
....................755 Cow No. 50........
......................536 Cow No. 60..........
May 8, 1917, end of fourth period.
Cow No. 21......................... 733 Cow No. 17..............................
Cow No. 25....................w No. 2............... Cow No. .... ............ .......695
Cow No. 33...... .... .......685 Cow No. 26.... ............ .............763
Cow No. 57........................... .. 665 Co No. 86.......................................620
Cow No. 62....................................650 Cow No. 41................................. 741
Cow No. 69 -... .... ....... ......762 Cow No. 50.................................. 60
Flagler .............. ........................515 Cow No. 60........... ............. ..... 729
BEEF HERD
Armour & Company of Chicago, Illinois, donated on February
16, 1917, a pair of Shorthorns to the Experiment Station. Roan
Lady No. 205097, born June 14, 1915, by Ruberta's Goods No.
283807, out of Gloster Pride 2nd No. 93031, bred by H. Rees &
Sons, Pilger, Nebraska. Thaxton's Royal No. 524679, born
..............................775
.............................680
.............................741
...........................602
.............................742
.......................... 582
.............................713
Annual Report, 1917 27R
April 1, 1916, by Kings Secret No. 369111, out of Josephine No.
71282, bred by James Brown, Dundee, Illinois. These are two
well-bred Shorthorns and are also good individuals and should
make a good foundation for a beef herd.
HOGS
Two Berkshire sows were purchased during the year. Lady
Premier Longfellow 24th No. 237652, out of Lady Premier
Longfellow 2nd No. 144047, by The Grandson's Duke No. 171000.
Rival's Maxima 16th No. 238020, out of Rival's Maxima 8th No.
207168 by Rival's Champion 10th No. 178000.
These two sows were bred to Lord Premier's Successor 5th
No. 216000. Lady Premier Longfellow 24th No. 237652 far-
rowed May 1, 1917, five sows and three boars. Rival's Maxima
16th No. 238020 farrowed May 20, 1917, four sows and two
boars.
PIG FEEDING EXPERIMENT
Sixteen pigs were used in the test. At the beginning of the
test the pigs averaged about 100 pounds per head. The sixteen
pigs were divided into two lots of eight pigs each. The test
began March 11, 1917, and continued until May 8, 1917. The
pigs in lot I were fed shelled corn only. The pigs in lot II were
fed shelled corn two parts and sweet-potato silage one part by
weight.
The following tables give the results in detail:
TABLE 12.-WEIGHTS AND GAINS IN POUNDS
SLoT I LOT I
Pounds Pounds
Weights at beginning of test, March 11, 1917 (8 pigs)........ 803.00 833.00
Weights at close of test, May 8, 1917......... ............ ......... 980.00 910.00
Gain in 59 days............................... ................... 177.00 77.00
Average gain per head........................................ 22.13 9.63
Average daily gain per head................................. ............... 0.38 0.16
Average daily gain per 1000 pounds live weight............. 0.79 0.57
Pounds of feed to make one pound of gain......... ........ 7.30 16.60
TABLE 13.-POUND OF FEED CONSUMED
I LOT I LoT
Pounds Pounds
Corn ............................... ........ ....-. .. 1298 826
Sweet-potato silage ....... ............. .......... ........ ...... 453
TABLE 14.-DAILY RATIONS, POUNDS PER PIG
I LOT I LoTII
Pounds Pounds
Corn ........... ............ ...... ... .. ................................... 2.75 1.75
Sweet-potato silage .. ... .......... ............................ ....... .96
Florida Agricultural Experiment Station
SILAGE CORN
Four varieties of corn were compared for yield of silage,
Mexican June, Martin's Improved, Blount's Prolific and Has-
tings' Prolific. These varieties were all planted at the same
time. The land on which they were grown was fairly uniform.
All varieties were given the same kinds and amounts of fertilizer
and the same cultivation. The yields were as follows: Mexican
June, 6.6 tons; Martin's Improved, 7 tons; Blount's Prolific, 9
tons; and Hastings' Prolific, 11.7 tons green material per acre.
Another noticeable difference in these varieties was the date of
maturing. Mexican June, Martin's Improved and Hastings' Pro-
lific matured at the same time; Blount's Prolific matured ten
days to two weeks earlier than any of the other varieties.
FLAX
The growing of flax was tried this year. Plantings were
made December 20, 1916, and January 23, 1917. The seed ger-
minated and inade a nice growth. The freeze of February 3
and 4, 1917, when the thermometer registered 17 and 180 Fahr.,
killed 90 to 95 percent of the plants. The few remaining plants
made a good growth, a goodly number of which attained a
height of fifteen to twenty inches.
JAPANESE-CANE FERTILIZER EXPERIMENT
This experiment is a continuation of the fertilizer experiment
discussed in the last report.
The Japanese cane in this experiment was planted January
7, 8, 9, 1914. The seed canes averaged about six feet in length
and it required 2,182 whole canes to plant one acre. For plant-
ing, the canes were cut into lengths averaging 15 to 18 inches.
The fertilizer in this experiment was applied in two applications
each year. The first application was made in the spring, the
secofid application in the summer. At the first application all
the phosphoric acid and potash and half the ammonia were
applied. The remainder of the ammonia was given as a second
application in July of each year.
Tables 15, 16 and 17 show the amounts.of fertilizer applied
and the yield obtained from each plot and the average yield for
three years.
In comparing the yields of green material for each year of
this test it is evident that there was a very marked decrease in
the yields from all the plots each year as compared with the
yields the first year, or 1914.
28R
Annual Report, 1917 29R
The kind of fertilizer applied seems to have had no influence
in maintaining the yield. The check plots seem to have de-
creased in yield in about the same proportion as the fertilized
plots. Plot 3, fertilized with barnyard manure at the rate of
thirty two-horse wagon loads per acre produced a heavy yield
the first year; the second year there was a decrease of nearly
60 percent, while the yield for the third year was practically
the same as that of the second year.
Comparing the yields from plots 1 and 2 we get a comparison
of the value of sulphate of ammonia and dried blood as a source
of ammonia for fertilizing Japanese cane. Plot 1 received sul-
phate of ammonia, acid phosphate, and sulphate of potash and
ground limestone. The yield of green material, for an average
of three years, was 13.7 tons. Plot 2 was fertilized the same
as plot 1 except dried blood was used instead of sulphate of
ammonia. The yield of green material, for an average of three
years, was 11.8 tons or a difference of 1.9 tons in favor of
sulphate of ammonia. Plot 3 fertilized with barnyard manure
produced the largest yield of any of the plots in the test. The
yield for an average of three years was 19.8 tons green material.
To get a comparison of the value of acid phosphate, floats and
Thomas slag we should compare the yields from plots 5, 6 and 8.
Plot 5 was fertilized with sulphate of ammonia, acid phosphate
and sulphate of potash. Plot 6 was fertilized with sulphate of
ammonia, floats and sulphate of potash. Plot 8 was fertilized
with sulphate of ammonia, Thomas slag and sulphate of potash.
The acid phosphate, floats and Thomas slag were not applied at
the same number of pounds per acre, but an equal amount of
phosphorus was applied to each plot.
Plot 5, on an average of three years, produced a yield of 11.8
tons of green material. Plot 6 during the same time produced a
yield of 12.1 tons, and plot 8 produced a yield of 10.5 tons green
material.
The acid-phosphate plot produced a yield of 1.3 tons more per
acre than did the Thomas-slag plot. The floats plot produced
a yield of 0.3 of a ton more per acre than did the acid-phosphate
plot, and 1.6 tons more than the Thomas-slag plot. These re-
sults would indicate that there is little or no difference in the
fertilizing value of acid phosphate and floats for fertilizing
Japanese cane. Of the three sources of phosphorus Thomas
slag produced the smallest yields of Japanese cane.
A comparison of plots 1 and 5 gives the value of ground lime-
Florida Agricultural Experiment Station
stone. These two plots were fertilized exactly alike except plot
1 received ground limestone and plot 5 did not. The fertilizer
was applied each year as given above, but the ground limestone
was applied in the spring of 1914 and again in 1916 at the rate
of 2,000 pounds per acre. The yields from these two plots show
an increase in yield of 1.9 tons on the ground-limestone plot.
Plot 4 fertilized with dried blood, floats and sulphate of potash
produced a yield of 10.8 tons. Plot 6, fertilized with sulphate
of ammonia, floats and sulphate of potash, produced a yield of
12.1 or a difference of 1.3 tons green material in favor of sul-
phate of ammonia. Dried blood and sulphate of ammonia were
not applied in equal number of pounds per acre, but equal
amounts of ammonia were applied to each plot.
The results obtained from plots 1 and 7 show the value of
acid phosphate as a fertilizer for Japanese cane. Plot 1 was
fertilized' with sulphate of ammonia, acid phosphate and sul-
phate of potash. Ground limestone was also applied in the
spring of 1914 and of 1916. The yield on this plot, for an aver-
age of three years, was 13.7 tons. Plot 7 that was fertilized the
same as plot 1 except that no acid phosphate was applied, pro-
duced a yield, for an average of three years, of 11.8 tons. This
shows a difference of 1.9 tons in favor of acid phosphate.
If we compare the yields obtained from plots 1 to 8 inclusive,
all of which received complete fertilizers, we see that plot 8
produced the smallest yield, or 10.5 tons green material. Com-
paring the yields obtained from the plots which received a com-
plete fertilizer with the yield obtained from the check plots we
see the increased yield secured by fertilizing. The check plots
produced less than one-half the yield secured from the fertilized
plots. The average yield of the two check plots for three years,
was 5.6 tons. The average of the eight plots which received a
complete fertilizer was 12.8 tons. The plot that produced the
heaviest yield was plot 3, fertilized with barnyard manure. The
next best yield was secured from plot 1, fertilized with sulphate
of ammonia, acid phosphate and sulphate of potash. Ground
limestone was also applied to this plot in the spring of 1914 and
of 1916.
In comparing the yields from the plots which received in-
complete fertilizers, where only two elements were applied, that
of plot 15, fertilized with sulphate of ammonia and sulphate of
potash, produced the best yield, 9.1 tons per acre. The next best
yield was from plot 11, fertilized with sulphate of ammonia and
30R
Annual Report, 1917
TABLE 15.-EFPECT OF COMPLETE FERTILIZER ON JAPANESE-CANE YIELDS
Fertilizer applied,
pounds per acre Yields er acre,
Yields per acre,
S in tons of
S 0 a o green material
Xo 0 t 3 Av- 0b
c S g I I 1914 1915 1916 er-
04 a E a 0 I age O
1 .. 84 84 -- 150. ....... 60 12000 17.03 13.30 10.85 13.7 244.6
2 .... ..-....- 123.5 ..- 1501 ........... 60 200014.42 12.95 8.23 11.8 210.7
3 ...... ................. *30 .-....-. .- .. ........ 32.67 13.65 13.21 19.8 353.5
4 ...... ........ 123.51 ........ ..... 75 .... 60 ........ 12.31 11.20 9.01 10.8 192.8
5 ...... 84 .. .. .... 150 .... ... 60 ........ 15.97 11.20 8.40 11.8 210.7
6 ...... 84 .......... ........ 75 ....... 60 ........ 17.11 12.16 7.18 12.1 216.0
7 ...... 84 ......... I...... ........ ...... ..... 60 2000 16.85 11.90 6.91 11.8 210.7
8 ..... 84 ..... ..... ... ... ........ 133 60 ........ 16.68 9.36 5.60 10.5 187.5
9,20.. Check plots, averaged yields 8.15 5.55 3.19 5.6 100.0
*Thirty two-horse wagon loads.
TABLE 16.-EFFECT OF INCOMPLETE FERTILIZERS ON JAPANESE-CANE
YIELDs-Two ELEMENTS USED
Fertilizer applied,
pounds per acre Yields per acre,
in tons of
S, go Sgreen material *J
.~ 0 4. +4 cc l 3S
5O cc 2v- 0 A
S I 4 0 S E 1914 1915 1916 er- o.
W- cn Z u2 i C: age U 0-
10 ...... 8 .................. ...... 000 12.77 7.17 3.06 7.6 135.7
11 ...... 84 .......... ... 75....... 14.38 8.31 3.85 8.8 157.1
12 ...... ... .. 123.5 .. 75..... 75 ......... .. ... 13.41 7.00 2.01 7.4 132.1
13 ...... ... .... 116.6 ........ 60 ...........14.11 7.35 3.50 8.3 1482
14 ...... ...... 123.5 ...... .......... 60 .......... 9.02 8.22 3.33 6.8 121.4
15 ...... 84 ........... ........ .......... 60 -.......... 12.10 8.75 6.65 9.1 162.5
9, 20.... Check plots, averaged yields 8.15 5.55 3.19 5.6 100.0
TABLE 17.-EFFECT OF INCOMPLETE FERTILIZERS ON JAPANESE-CANE
YIELDS-ONE ELEMENT USED
Fertilizer applied,
pounds per acre
Yields p
in to
er
So 4 oS green mat
| ,; o I : i,
0 5 0 Z i o) 0 |
4 1 1 o I"4 1914 1915 I!
16 .. -..... ..... ----....----- ----- 133 .. ........ 9.14 7.70 3
17 .... .......-.. .......... ............ .... ..... . .. 60 9.09 7.08 3
18 .... .....i -....... -- ......... 75 .- ....-. ..-.. 6.79 5.42 2
19 .... ... . ....150.......... .. 8.40 5.68 2
21 .... ........ 123.5 .......... ......... .. .. .... 7.05 6.56 2
22 .... ......... 116.6 I ........ ........ ... 14.03 7.78 5
23 .... 84 1....... ......... .......... .... -- 9.45 7.70 4
9,20.. Check plots, averaged yields 8.15 5.55 3
acre, x
of f )
erial '
A -g 3
Av- 2 b
916 er- o.s
agei
.76 6.8 121.4
.85 6.6 117.8
.63 4.9 87.5
.98 5.6 100.0
.80 5.4 96.4
.25 9.0 160.7
.73 7.2 128.5
.19 5.6 100.0
31R
Florida Agricultural Experiment Station
floats, which produced a yield of 8.8 tons. The smallest yield
was from plot 14, fertilized with dried blood and sulphate of
potash, which produced a yield of only 6.8 tons.
Comparing the yields of plots 10, 11, 12, 13, 14, and 15 with
the two check plots we find a difference of 2.4 tons green ma-
terial in favor of the incomplete fertilizer.
Comparing the yields from those plots which were fertilized
with only one element, plot 12, fertilized with nitrate of soda,
produced the best yield, 9 tons green material per acre. The
next best plot was 13, fertilized with sulphate of ammonia, which
produced a yield of 7.2 tons green material per acre.
JAPANESE CANE
YIELDS OBTAINED BY REPLANTING
Some interesting results have been secured from the eight
plots of Japanese cane that were replanted on March 6, 1915.
Previous to 1915, the plot of ground on which this test was
conducted had grown Japanese cane for six years. In the spring
of 1915 the Japanese cane was plowed up and the cane replanted.
In replanting care was taken to replant the rows in the same
place the cane had stood before. Each plot of replanted cane
was fertilized the same as the plots had been for the previous
six years. The kinds and quantities applied are shown by table
18.
TABLE 18.-FERTILIZERS USED IN REPLANTING TEST, POUNDS PER ACRE
PLO| PLOT PLOTI PLOT PLOT PLOT PWLr PLOT
Fertilizer I II III IV V VI VII VI
Lbs. Lbs. Lbs. Lbs. Lbs. Lbs. Lbs. Lbs.
Dried blood .................. 112 ..... 112 .. 112 .......... 112 112
Sulphate of ammonia........ ...... ......... 72 .......... 72 .......... .......
Muriate of potash ............ 84 84 .......... 84 84 .............. .........
Sulphate of potash............ ........ ......... .......... .......... ...... 84 84 84
Acid phosphate ........... ....... 224 224 224 224 224 224 224
Ground lim stone .............. .......... .......... .... .. .......... .......... .......... .......... 2000
TABLE 19.-YIELDS OF JAPANESE CANE IN TEST, TONS GREEN MATERIAL
PER ACRE
S1915 | 1916 i Average
Tons Tons Tons
Plot I.................................. ........... 29.5 21.4 25.4
Plot II... ............................ ... 31.9 15.6 23.7
Plot III..................................... ...... 18.0 3.8 10.9
Plot IV................................................ 24.2 12.5 18.3
Plot V......................................... 29.7 10.6 20.1
Plot VI............................. ............... 24.9 9.6 17.2
Plot VII.................... ............... ....... 27.3 7.7 17.5
Plot VIII .....-.......... ... ................ 22.5 .12. 17.3
32R
Annual Report, 1917
Table 19 gives the yield in tons green material from each plot
for 1915 and 1916, and the two-year averages. The noticeable
facts in the yields given above are that there was a marked
decrease in yield in 1916. Plot 3 produced the smallest yield.
This was the plot that had received no potash for six years pre-
vious to the beginning of this test.
CORN FERTILIZER EXPERIMENT
The land on which this test was conducted had been used for
the Japanese-cane fertilizer experiment, which was under ob-
servation during 1909 to 1914. The corn was planted in the
same rows in which the Japanese cane had grown, six feet apart.
Each plot was given the same kind and amounts of fertilizer that
the Japanese cane had received in previous years. (See table 18.)
Following are the yields in bushels per acre from each plot.
Plot I, 24; plot II, 23.3; plot III, 23.0; plot IV, 26.1; plot V, 25.4;
plot VI, 26.7; plot VII, 27.4; and plot VIII, 19.2.
SWEET-POTATO FERTILIZER EXPERIMENT
The sweet-potato fertilizer experiment was begun the spring
of 1915. The yields of 1915 were given in the last annual report.
Table 20 shows the kinds and amounts of fertilizers applied
per acre, and the yields obtained.
TABLE 20.-FERTILIZERS USED AND YIELDS OF SWEET POTATOES OBTAINED
PLOT PLOT PLOT PLU O PLOTT P PLLOTPLT
Fertilizer I II III IV V VI VII VIII
Lbs. Lbs. Lbs. Lbs. L. Lbs. Lbs. Lbs. I Lbs.
Dried blood, per acre. 112 .......... 112 .......... 112 .......... 112 112
Sulphate of ammonia,
per acre ....... .... ..... .............. ........ ..- 72 .. 72 ........ ...
Muriate of potash,
per acre -......... ........ 84 84 .......... 84 84 .........................
Sulphate of potash,
per acre ......... ............................ .. 84 84 84
Acid phosphate, per acre.. ..........224 224 4 2 224 224 224
Bu. Bu. Bu. Bu. Bu. Bu. Bu. Bu.
Yield, bushels per acre,
1915 ....... ............... 245.0 221.6 99.6 259.6 252.0 216 222.0 269.6
Yield, bushels per acre,
1916 .......................... ... 158.6 177.6 86.4 228.8 182.6 128 203.2 110.4
Average yield for 2 years 199.31 199.6 93.0 244.2 217.3 172 212.6 190.0
The yields of all plots in 1916 were less than those produced in
1915. Plot IV that produced the largest yield in 1915 produced
the largest yield in 1916. Plot III that produced the smallest
yield in 1915 produced the smallest yield in 1916. These results
3
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34R Florida Agriculturat Experiment Station
would indicate that potash is an important fertilizer element
for sweet potatoes. Plot II which received no ammonia produced
an average yield of 199.6 bushels per acre. This would indicate
that ammonia is not as important as potash in fertilizing sweet
potatoes.
Respectfully,
JOHN M. SCOTT,
Animal Industrialist.
Annual Report, 1917
REPORT OF PLANT PHYSIOLOGIST
P. H. Rolfs, Director.
SIR: I submit the following report of the Plant Physiologist
for the fiscal year ending June 30, 1917.
Particular attention has been given during the year to the fol-
lowing lines of work: (1) A study of the conditions under
which injury to citrus trees may be induced by the addition of
ground limestone to the soil; (2) a field study of the influence
of fertilizers upon the coloration of grapefruit at maturity;
(3) a field study of the influence of fertilizers containing dif-
ferent ratios of phosphoric acid and potash upon the vegetative
growth and fruit production of oranges and grapefruit trees;
and (4) a field study of the combination, stable manure-legumes-
phosphate rock, as a source of ammonia and phosphoric acid for
citrus trees.
INJURY TO CITRUS TREES BY THE IMPROPER USE OF GROUND
LIMESTONE
In the annual report of this laboratory for 1916 (Fla. Agr.
Exp. Sta. Ann. Rep. 1916, p. 38R) and in Bulletin 137 of this
Station, attention was called to an injury of citrus trees that
was apparently induced by ground limestone which had been
added to the soil. The most striking characteristic of the injury
was a marked frenched (lack of green color between the veins)
to chlorosed (complete whitened or yellowed) condition of the
leaves. Other characteristics were incomplete or total defolia-
tion of the terminal branches, especially during the winter sea-
son, and a dry, hard appearance of the bark, which with the
frenching and yellowing gave the tree a general unthrifty and
starved appearance. Many of the terminal branches showed
multiple buds. Shoots developed from an exceptional number
of the nodes giving a somewhat bushy appearance to the tree.
There was a gradual dying back of many of the defoliated ter-
minals, especially during the winter season. The fruitfulness
of the tree was largely destroyed, very little fruit being pro-
duced. That which was borne was usually of poor quality and
often rough and stunted.
In the groves where the limestone had been used widespread
and the injury had developed, there was considerable variation
in the amount and extent of the injury. Many trees were found
that showed no evidence of the injury, while the amount of
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Florida Agricultural Experiment Station
injury in those showing it varied from a mere frenching of the
foliage to the extreme conditions described above.
The injury did not develop in all groves where ground lime-
stone had been applied to the soil. Virtually all cases observed
of injury to trees in the field occurred in trees less than seven
to ten years old, planted on sandy soils having a tendency to
dryness and lacking in humus. Trees planted on lands well
supplied with moisture and humus appeared to be uninjured
by the addition of the limestone.
The injury did not develop immediately after the application
of the limestone. Usually the first noticeable effect of the lime-
stone was a stimulation to growth. After several months this
was followed by a period in which the injury developed. The
first indication of the injury was the frenching of the foliage.
Both oranges and grapefruit were affected.
The injury was not confined to the citrus trees, but also af-
fected the cover crops. Beggarweed and cowpea seedlings be-
came frenched, turned yellow and died. The crabgrass grew
very sparsely. Velvet beans made very little growth. The result
was that the soil was more or less bare at the time of year when
it should have been well covered with growth. Even lemon
sprouts developing from exposed roots of the trees showed the
affectation.
As previously mentioned, the injury appeared to be induced
by the ground limestone that had been added to the soil. In
order to obtain more positive evidence of the limestone as a
causal agent, and more information concerning the conditions
under which the injury occurs, the following experiments were
outlined and carried out.
POT EXPERIMENT WITH GROUND LIMESTONE
This experiment was carried out in the greenhouse during the
spring of 1917, in two groups of six-inch flower pots. Each
group consisted of thirteen series, and each series of ten pots,
of which five were filled with clear sand from the shores of Lake
Weir, and five with a sandy loam from a velvet-bean field, and
well supplied with humus.
Each pot in group one, except the thirteenth series which
received no fertilizer, was given the following fertilizer:
Cottonseed meal.............................. 7.5 grams
Acid phosphate............................ .. 7.5 grams
High-grade sulphate of potash.............. 2.5 grams
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Annual Report, 1917
Each pot in group two, except the thirteenth series which re-
ceived no fertilizer was given:
Sulphate of ammonia........-....-.. .... 2.4 grams
Acid phosphate......................................... 7.5 gram s
High-grade sulphate of potash............. 2.5 grams
Finely ground limestone was applied to the different series
of the two groups in such amounts that it constituted a certain
percentage of the dry weight of the soil in the pot. The amount
of limestone contained in the soil of the different series of each
group was as follows:
Series I ...... ................... 1 percent
Series II -............ ... .. 3 percent
Series III -.........5........... 5 percent
Series IV ............-...... .. 8 percent
Series V ...........-- ....... 12 percent
Series VI ...................... 18 percent
Series VII .................25 percent
Series VIII ................35 percent
Series IX ...... ..........50 percent
Series X .............----..75 percent
Series XI ..... ...----...- 95 percent
Series XII ....................none (with fertilizer)
Series XIII ...............none (and without fertilizer)
The limestone used was not a fresh lot, but some that had been
exposed to the weather for more than a year. It was mixed with
the soil about four weeks before the seed were planted, while the
fertilizer was added about two weeks before planting. Both
were mixed with the whole of the soil in the pot.
The walls of the pots were soaked with hot paraffin before
using, but the opening in the bottom was left for drainage.
The moisture content of the soil was kept at as near an opti-
mum as possible by the usual method of watering greenhouse
plants, thruout the experiment. While the soil was not flooded,
there was more or less drainage from the pots which probably
carried away some of the soluble food materials. As a conse-
quence, the plants began to show evidence of nitrogen hunger
after about four-months' time.
Five grapefruit seeds from marketable fruits and selected for
uniformity were planted in each pot, making fifty plants for
each series.
RESULTS
None of the plants in any of the series showed any injury to
the first two leaves developed after the plants came up. The
first injury noted was in the third and fourth leaves, and those
of succeeding development. The injury consisted of a yellowing
and stunting of the plants as a whole. The yellowing was of
three types:
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Florida Agricultural Experiment Station
(1) A chlorosis in which the leaves were virtually devoid
of green color. Such leaves showed a nearly uniform yellow to
white color. In some cases streaks of green showed along the
midrib, but the reniainder of the leaf was yellow;
(2) A frenching consisting of a lack of green color in the
leaf areas between the larger veins, giving the leaves a mottled
appearance-which is a condition of partial chlorosis and prob-
ably shows the region of initial affectation by the factor that
causes the chlorosis;
(3) A light to yellowish-green color of the leaf as a whole.
The chlorosed leaves hardly ever reached complete develop-
ment in size, and usually dropped early. The chlorosis showed
when the leaves were first evident in the opening buds.
The frenched leaves were often undersized, but seldom
dropped. The light green leaves were nearly always of normal
size, and lacked only the depth of color.
Not all of the leaves or plants in a series showing injury were
affected. There was considerable variation in this respect. In
the series with the lowest percentage of limestone in the soil,
only scattered leaves and plants were affected, while in the
higher percentage series all plants were affected, excepting a
few individuals.
The chlorosing and frenching were always noticed to be present
in the leaves as they emerged from the bud. None of the leaves
that were deep green and uniform in color in the developing bud
were seen to become chlorosed or frenched in later stages of
development. However, these effects were sometimes present
only as traces in the earlier developmental stages of the leaf,
but became more prominent in the later stages.
In the more severely affected plants, the terminal buds were
injured. These plants seldom developed beyond the fifth or
sixth node, whereas unaffected plants developed fifteen or more
nodes during the same period of time.
GROWTH STIMULATION BY LI EroNE
Stunting of the plants was confined almost entirely to the soils
containing 75 percent and more of limestone. There was appar-
ently some stimulation of growth by the lower percentage of
limestone.
Table 21 shows the average number of leaves or nodes per
plant in each series at the end of the second flush of growth.
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Annual Report, 1917
TABLE 21.-SHOWING STATUS OF CITRUS SEEDLINGS AT END OF SECOND
FLUSH OF GROWTH
Limestone, percent. .... 131 51 81 12- 181 251 351 501 751 951 0 0
C. S. M.*-Sand............. 6 7 7 10 77 6 6 7 48 5
Loam.......... 156 17 20 20 1514 21 20 7 10 7
S. A.t-Sand................. 5 5 5 8 912 9 10 7 3 5 4
Loam ..........7 10 20 20 20 2019 18 15 5 10 7
*Cottonseed meal. tSulphate of ammonia.
From this table it is seen that, in this experiment, those soils
fertilized with cottonseed meal, and containing 8 percent lime-
stone gave the most growth, whereas of those fertilized with
sulphate of ammonia, the soils containing 18 percent gave the
most. Where 75 percent and more of limestone was contained
in the soil, the plants were stunted.
The limestone was the most effective in increasing growth
where it was used on the loam soils; with two exceptions the
increase over that produced by the fertilizer without limestone
varied from about 50 to 100 percent. The exceptions noted were
the 1 percent and 3 percent limestone soils fertilized with sul-
phate of ammonia. In sand cultures with grapefruit seedlings
conducted during 1914 and 1915 (Fla. Agr. Exp. Sta. Ann.
Reports for 1914 and 1915) it was shown that the fertilizer
combination, sulphate of ammonia, acid phosphate and sulphate
of potash, produced an amount of growth that was but little
greater than that produced in the absence of fertilizer. But the
addition of air-slaked lime to soils fertilized with this combina-
tion produced a large increase of growth. From these experi-
ments it may be inferred that the 1 percent and 3 percent fime-
stone in the soils had failed to counteract the effect of the fer-
tilizer combination acting alone.
The limestone in the sandy soil fertilized with cottonseed meal
produced virtually no increased growth, while that with the
sulphate of ammonia produced an increase that varied from none
to more than 100 percent.
Both the sandy and the loam soils fertilized with cottonseed
meal and sulphate of ammonia and containing 75 percent and
more of limestone produced very little growth. Apparently,
the limestone in these amounts was an inhibitor of growth.
EFFECT OF LIMESTONE ON THE LEAP COLORATION
CHLOROSIS OF THE LEAVES
Development.-The first evidence of any deleterious effect of
the limestone upon the plants was noted in those on the sandy
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Florida Agricultural Experiment Station
soils containing 50 percent and more, and in those on the loam
soils containing 75 percent and more, of this material. The third
and fourth leaves of a number of plants in these series showed
complete chlorosis. The lack of green color was present in the
leaves when they were first evident in the unfolding buds. The
affectation showed at practically the same time in plants of the
corresponding series of both the cottonseed-meal and sulphate-of-
ammonia groups.
The next series to show affected plants were those in sandy
soils containing 18 percent and 25 percent limestone. With two
exceptions the fifth leaves on these plants were the first to show
the chlorosis, altho a number of the fourth leaves showed french-
ing.
With further development of the plants, the number of leaves
affected in these series increased. It also showed anew in other
series. In the soil with the lower percentages of limestone,
frenching was the predominant affectation.
TABLE 22.-PERCENTAGES Or GREEN, FRENCHED AND COMPLETELY CHLO-
ROSED LEAVES 1N CutrUNSl~EI) MEAL-LIMESTONE SERIES
Limestone in Kind of Green Frenchedl Completely Chlorosed
Soil Soil Leaves Leaves I Leaves
Percent I Percent Percent Percent
1 ...... Sand 94.7 3.3 2.0
Loam 99.4 .6 0.0
3 Sand 90.1 9.2 .7
Loam 94.8 5.2 .0
S ....... ..... Sand 82.6 14.8 2.6
Loam 87.6 12.0 .4
8 ........ Sand 74.1 23.1 2.8
Loam 81.4 18.1 .5
12. ....... Sand 79.4 17.2 3.4
Loam 78.0 21.4 .6
18 .... .. Sand 59.3 29.3 11.4
Loam 88.4 11.6 .0
25 ... ........ Sand 59.6 34.5 5.9
Loam 81.9 18.1 .0
35 .. Sand 53.2 34.6 12.2
Loam 76.5 21.2 2.3
50 ..... ... Sand 53.8 29.0 17.2
Loam 65.3 24.2 10.5
75....... Sand 51.5 23.5 25.0
Loam 61.2 19.4 19.4
95 Sand 54.3 25.9 19.8
I Loam 54.2 18.4 27.4*
O .... Sand 77.3 22.7 .0
SLoam 97.4 2.6 .0
Tlhe greater percentage of chlorosed leaves in the loam soil is explained
by the fact that many of these leaves had dropped soon after emerging
from the bud and previous to the time this enumeration was made.
tin the series where neither fertilizer nor limestone was used, there were
no fronched or chlorosed leaves, but G8%' of those on the aalndy soil and
61% of those on the loam soils showed a light green color.
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Annual Report, 1917
TABLE 23.-PERCENTAGES OF GREEN, FRENCHED AND COMPLETELY CHLO-
ROSED LEAVES IN SULPHATE OF AMMONIA-LIMESTONE SERIES
Limestone in
Soil
Percent
1..... ..................
3.........................
5.............................
8.................... .......
12.............................
18..............................
25..................... ......-
35........ ........... ....
50..... ...........
75 ............. .......
95..............................
0.............................
Kind of
Soil
Sand
Loam
Sand
Loam
Sand
Loam
Sand
Loam
Sand
Loam
Sand
Loam
Sand
Loam
Sand
Loam
Sand
Loam
Sand
Loam
Sand
Loam
Sand
Loam
Green Frenched
Leaves I Leaves I
Percent
89.1
97.5
87.0
98.1
86.0
88.2
80.8
78.6
63.8
66.8
60.8
65.5
67.8
66.1
55.8
64.5
50.8
57.6
49.0
54.2
46.3
47.3
82.7
89.2
j
Completely Chlorosed
Leaves
Percent
.0
.0
.0
.6
.0
.0
.7
.0
.0
.0
7.4
.0
4.7
.0
8.3
1.1
27.5
5.1
29.0
22.3
20.4
27.5*
.0
.0
*The greater percentage of chlorosed leaves in the loam soil is explained
by the fact that many of these leaves had dropped soon after emerging from
the bud and previous to the time this enumeration was made.
At End of First Flush of Growth.-At the end of the first
flush of growth, five to seven leaves had been formed. Tables
22 and 23 show the percentage of leaves showing the different
degrees of affectation at that time. The data for the tables were
collected under the three headings-Green, Frenched, and Chlo-
rosed. The light green leaves were classified as green, because
the number showing this color distinctly was not great, and
because of the difficulty of distinguishing it from other shades
of the green. In these tables, the results of the series receiving
neither fertilizer nor limestone are omitted. None of the leaves
on these plants were frenched or chlorosed. Sixty-eight percent
of the leaves of the plants in the sand and 61 percent of those
in the loam soil were distinctly of the shade of yellowish-green,
indicating nitrogen hunger.
From the tables it is seen that at the end of the first flush of
growth the leaves of the plants growing in the soils without
limestone but with fertilizer, showed no complete chlorosing of
the leaves, but nearly 23 percent of those on sandy soils and
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I
Percent
10.9
2.5
13.0
1.3
14.0
11.8
18.5
21.4
36.2
33.2
31.8
34.5
27.5
33.9
35.9
34.4
21.7
37.3
22.0
23.5
33.3
25.2
17.3
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Florida Agricultural Experiment Station
about 3 percent of those in the loam soils showed frenching. The
Entire absence of either frenching or chlorosing in the plants in
the soils without limestone and fertilizer, and the development
of frenching only in those growing on the fertilized soils, indi-
cates that the fertilizer is a factor in leaf disturbance.
The complete chlorosing of the leaves occurred only in the
plants growing in soils containing limestone. From this it is
to be concluded that the complete chlorosis of the leaves is to be
attributed to the action of the limestone. It may be causing it
directly or it may be only intensifying the action of the fertilizer.
Relation to Quantity of Limestone.-The extent of the chloro-
sis was for the most part directly related to the amount of lime-
stone contained in the soil. The smaller number of leaves were
affected where the lesser amounts were present in the soil and
the larger number where the larger amounts were present. In
the corresponding series of both groups on sandy soil the per-
centages of affected leaves were small until the limestone content
was more than 12 percent. The first large increase in affected
leaves was made when the limestone content reached 18 percent.
There was a decrease on 25 percent limestone soil, but an in-
crease again on the 35 percent limestone soils, with further
increases as the limestone content of the soil increased.
No explanation can be made for the small number of affected
leaves on the 25 percent limestone soil as compared with that on
the 18 percent soil. The decrease on the 95 percent limestone
soil is due to the dropping of many of the chlorosed leaves soon
after emerging from the buds. But no such extensive dropping
was observed in the 25 percent limestone series.
On the loam soils of both series, there was very little affecta-
tion until the limestone content reached 35 percent, but from
this point there was an increase with each increase of the amount
of limestone contained in the soil.
Relation to Soil Type.-The amount of chlorosis in the plants
of all series on the sandy soils was greater than in those on the
loam soils, excepting the series with 95 percent limestone. This
variation is known to be due to the dropping of the chlorosed
leaves in an early stage of development; whereas the percentages
shown in the table are based on the number of affected leaves
present at the time of counting. From this it may be concluded
that the loam soil is an inhibitor to the deleterious effect of the
limestone.
Relation to Fertilizer.-As noted elsewhere, the experiment
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Annual Report, 1917
was conducted in two groups. The soil in the pots in one group
was given a complete fertilizer consisting of cottonseed meal,
acid phosphate, and high-grade sulphate of potash, while that
in the other group was given a fertilizer consisting of sulphate of
ammonia, acid phosphate and high-grade sulphate of potash.
The two fertilizers carried thle same amounts of plant food and
differed only in the character of the sources carrying the am-
monia.
In both the cottonseed-meal and the sulphate-of-ammonia
groups, practically no complete chlorosis was produced in the
plants on the loam soils containing 25 percent and less of lime-
stone. But where cottonseed meal was used on the sandy soils
some completely chlorosed leaves were produced by all percent-
ages of limestone; whereas with sulphate of ammonia as the
fertilizer on the same soil limestone percentages as high as 12
percent produced virtually none.
The loam soils containing 25 percent and 50 percent of lime-
stone and fertilized with cottonseed meal, each showed a greater
amount of complete chlorosis than the same fertilized with sul-
phate of ammonia. But when the limestone content of this soil
was increased to 75 percent and beyond, the reverse was true.
Similarly, the sandy soils containing 18 to 35 percent inclusive
and fertilized with cottonseed meal produced a greater amount
of complete chlorosis than the same soils fertilized with sulphate
of ammonia. But beyond 35 percent the reverse was true. Ap-
parently the lower percentages of limestone in sandy soils were
not so active in inducing complete chlorosis where sulphate of
ammonia was used as the source of ammonia in the fertilizer.
But the higher percentages were more active.
The fact that virtually no complete chlorosis resulted from the
lowest percentages of limestone in the loam soils with either
fertilizer and that a considerable amount was present in the
plants on the sandy soil fertilized with cottonseed meal, indicates
that the pure organic matter in itself in the soil is not the
inhibiting factor, but that the degree of decomposition, or some
other such factor, is probably of more importance.
FRENCHING OF THE LEAVES
Frenching is a condition of incomplete chlorosis of the leaf
and consists of a lack of green color in the areas between the
larger veins of the leaves. The region bordering the veins re-
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Florida Agricultural Experiment Station
tains the normal green color. This type of chlorosing gives the
leaves a mottled appearance.
There is some uncertainty as to whether the frenching is an
early stage in the development of the complete chlorosis and
that the yellowed areas represent the place of initial affectation,
but it is assumed that such is true.
The determination as to whether the leaf will be frenched
or completely chlorosed is made while the leaf is still in the bud
or is developing from the bud. No case has been observed where
a frenched leaf became completely chlorosed after it had attained
a distinguishable size. Neither have completely greened leaves
been observed to become frenched or completely chlorosed,
altho these conditions may become more prominent as the leaves
unfold.
A complete yellowing of green leaves often occurs wherever
the plants are subjected to nitrogen hunger or are injured by a
lack of drainage or by diseases or pests. But this type of leaf-
yellowing is quite different from the complete chlorosis asso-
ciated with line injury, altho sometimes variations of the two
types occur which are hard to classify.
Tables 22 and 23 show the percentages of leaves in the dif-
ferent series that show frenching. The relationship of this
affectation to the kind of fertilizer and type of soil used does not
stand out so clearly as in the case of the complete chlorosing of
the leaves. More or less frenching occurs in plants of all the
series, including those where fertilizer was used but the lime-
stone omitted. It was entirely absent only in the series where
neither fertilizer nor limestone was added to the soil. It was
present in less amounts where from 1 to 3 percent of limestone
was present in the soil, but increased to a rather large amount
with the higher percentages. In general it was present in larger
amounts in the plants fertilized with sulphate of ammonia than
in those fertilized with cottonseed meal. With one exception
the larger amount of frenching in the group fertilized with cot-
tonseed meal was in the plants on the sandy soils. But in the
sulphate of ammonia group, excepting the 1 percent and 3 per-
cent limestone, there was little difference in amount on the two
soils.
FURTHER HISTORY OF THE EXPERIMENT
The experiment was continued until the end of the second flush
of vegetative growth. At this time a considerable amount of
yellowing indicative of nitrogen hunger was evident in many of
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Annual Report, 1917
the series. This was considered to be a disturbing factor. There-
fore, the experiment was considered closed and the notes made
at this time were not given consideration.
The results of the experiment give additional evidence that
ground limestone may under certain conditions induce injury to
citrus trees.
CONCLUSIONS
1. In this experiment the grapefruit seedlings showed a dis-
tinct injury from the presence of ground limestone in the soil.
2. Two types of yellowing characterize the injury: (a) a
frenching or lack of green color in the areas between the largest
veins, and (b) a chlorosis consisting of a more or less complete
yellowing or whitening of the leaves.
3. These injuries occur in the leaves while they are yet in
the bud, or are emerging from the bud. As the leaves emerge
and develop the effect becomes more prominent.
4. It is assumed that frenching is chlorosis that has been ar-
rested in an early stage of development, but proof is lacking. No
case of frenching has been observed to develop into complete
chlorosis.
5. In the experiment the complete chlorosing is a distinguish-
ing characteristic of the limestone injury. It did not occur in
the absence of limestone from the soil.
6. Frenching is a characteristic of the limestone injury, but
not a distinguishing characteristic. It occurs in the plants on
the fertilized soils containing no limestone. It also occurs in
plants on soils containing limestone, but unfertilized. (Fla. Agr.
Exp. Sta. Ann. Rep. 1916, p. 48R.)
7. Both frenching and complete chlorosis have a quantitative
relation to the limestone in the soil. The largest amounts oc-
curred in plants on soils with the largest percentages of lime-
stone.
8. The frenching and complete chlorosing are also influenced
by the kind of ammonia fertilizer added to the soil. In these
experiments, cottonseed meal was used as representative of the
organic sources of ammonia and sulphate of ammonia of the
mineral sources.
9. Both sources of ammonia used in soils without limestone
induced frenching, but not the complete chlorosis. More french-
ing was produced by these fertilizers on the plants on the sandy
soils than in those on the loam soils.
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Florida Agricultural Experiment Station
10. In the sandy soils containing limestone, cottonseed meal
was more or less favorable for the production of complete chlo-
rosis. Sulphate of ammonia was, to a limited extent (especially
with the lower percentages of limestone), an inhibiting factor to
its development.
11. More injury was induced by the limestone in sandy soils
than by that in loam soils.
FERTILIZER EXPERIMENT WITH CITRUS SEEDLINGS
In the annual reports of this Station for 1913, 1914 and 1915,
reports were made of experiments carried out to compare the
effect of varying sources of ammonia and phosphoric acid upon
the growth of grapefruit seedlings in sand and in loam soils.
The sources of ammonia used were sulphate of ammonia, nitrate
of soda, dried blood, and nitrate of potash. The sources of
phosphoric acid used were acid phosphate, dissolved bone black
and basic slag. A complete fertilizer was used, high-grade sul-
phate of potash being the source of potash in all cases excepting
where nitrate of potash was used as the source of ammonia.
Three series were included where air-slaked lime was used alone
and in combination with sulphate of ammonia and acid phosphate
and with dried blood and acid phosphate. In these experiments,
with certain exceptions, the sources of ammonia and phosphoric
acid were compared only on the basis of one ratio, which was 5
percent ammonia to 6 percent phosphoric acid. These were
assumed to be proper ratios for their use.
During the fiscal year pot experiments were carried out with
sand and loam soils, comparing these sources on the basis of
higher and lower ratios. It was found that the ratio used in
the original experiments gave the best growth, and was the
proper one to use as a basis for the comparison of the sources.
The results of these experiments will be published elsewhere.
FIELD EXPERIMENTS WITH FERTILIZERS
INFLUENCE OF FERTILIZER TREATMENT ON THE COLORATION
OF GRAPEFRUIT
As has been pointed out in previous reports, from certain
points of view the results of fertilizer experiments carried out in
the greenhouse or in the field are not alone conclusive; each
should be supplemented by the other. On the other hand, there
are certain experiments that can be carried out only in the field.-
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Annual Report, 1917
During the spring of 1914, opportunity was offered by the
Del Oro Fruit Company of Clearwater, Fla., to assist them in
outlining field experiments with fertilizers. The grove consisted
of large bearing grapefruit trees of unknown variety, budded on
a rough lemon stock. The grove was originally a lemon grove;
but was budded to grapefruit after the freeze of 1895. It is
planted on Norfolk fine sandy soil, which is underlaid at vary-
ing depths by a sand clay. For several years previous to the
summer of 1912, three applications a year of a fertilizer made
up from sulphate of ammonia, steamed bone, acid phosphate,
double manure salt and high-grade sulphate of potash, analyzing
3 percent to 4 percent ammonia, 10 percent phosphoric acid and
10 percent potash, were given the grove. In this fertilizer,
somewhat more than half of the total phosphoric acid was carried
by the steamed bone.
The vegetative growth made by the trees and the amount and
quality of the fruit produced were highly satisfactory. But a
considerable percentage of the fruit at maturity showed a green-
ish tint that reduced its market value. The greenish tint was
found to be due to areas in which chlorophyll remained untrans-
formed in the deeper subepidermal tissues. A study of the
situation indicated that the cause of this lack of coloration was
due either to the effect of the stock upon which the trees were
budded, or to the method of feeding the trees. Since it was not
feasible to carry out any experiments with the effect of the
stock on the scion, it was decided to outline experiments on the
assumption that the cause was in some way related to the fer-
tilizer that had been given the trees.
The general type of vegetative growth made by the trees was
suggestive that this growth was being materially influenced by
the organic ammonia contained in the steamed bone of the fer-
tilizer. It was thought to be possible that the organic ammonia
stimulated a slow growth thru the winter season that prevented
the trees from going into a proper condition of dormancy
whereby the fruit would yellow normally. Therefore, the experi-
ment was outlined on a basis to determine this point.
The grove was divided into eleven plots, and the following
variations made in the fertilizer treatment. In the following
description of the treatment for each plot, the fertilizer, which
is the same as that used previous to 1912, is spoken of as the
standard fertilizer.
Plot 1. The standard fertilizer was used for the spring and
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Florida Agricultural Experiment Station
summer application. In the fertilizer for the winter application
all of the phosphoric acid was carried as acid phosphate and this
acid phosphate was applied separately on September 1. The re-
mainder of the fertilizer was applied in November at the regular
time for the winter application.
The acid phosphate was applied in September on the assump-
tion that it tended to stimulate growth, which was a condition
the experiment sought to avoid during the winter season. It
was thought that by applying it September 1 its stimulating
effect would be dissipated before the mid-winter season.
Plot 2. The fertilizing plan for this plot consisted of omitting
the ammonia entirely from the fertilizer for all applications
until the trees showed some indication of nitrogen hunger, and
from that time to apply an amount of nitrate of soda carrying
the equivalent of 1 percent ammonia that was in the standard
fertilizer. In order to omit all ammonia it was necessary to
omit all steamed bone from the fertilizer, hence the whole of
the phosphoric acid for the plot was carried as acid phosphate.
This treatment is practically the same as that which was being
given all the trees included in plots 1, 2 and 3 during the Novem-
ber and March applications of fertilizer previous to the summer
the experiment was started. The purpose of the treatment was
to determine the effect of incomplete ammonia starvation upon
the coloration of the fruit.
Plot 3. In the years previous to 1914, beggarweed had been
grown as the cover crop in the grove. This crop has made a
rather heavy growth and necessarily contributed to the organic
type of growth present in the trees. Therefore, the plan of the
experiment called for discouraging the growth of the beggar-
weed during the season of 1915 and thereafter, in all parts of the
experiment excepting in plot 3; here it was to be allowed to
grow as previously. The plot was given the standard fertilizer
at each of the three applications in the year.
Plot 4. The standard fertilizer contained 4 percent ammonia
for the spring application and 3 percent for the summer and fall
applications. In this plot 4 percent ammonia was used for all
applications. The purpose was to determine the influence of
increasing the ammonia in the fertilizer upon the coloration of
the fruit.
As a part of another experiment this plot was left unsprayed
during the first year of the experiment.
Plot 5. The standard fertilizer was used thruout the year on
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Annual Report, 1917
this plot. One month after the summer application of fertilizer,
3 pounds of sulphate of iron was applied to the soil about each
tree. Since iron is necessary for chlorophyll formation, it was
thought that perhaps an excess of iron in the soil might have a
beneficial effect upon its transformation during the fall and win-
ter season.
Plot 6. The standard fertilizer was used for the fall applica-
tion but for the spring and summer months nitrate of soda was
used instead of sulphate of ammonia. The purpose was to de-
termine the influence of the different sources of ammonia used
at different periods of the year.
Plot 7. A fertilizer differing from the standard only in that
raw bone was substituted for steamed bone was used for each
application in the year.
Plot 8. The same fertilizer treatment was given this plot as
plot 4. It differed from plot 4 in that it was sprayed the first
two years of the experiment, whereas plot 4 was not.
Plot 9. This plot received the same treatment as plot 5, ex-
cepting that 6 pounds of sulphate of iron was used per tree in-
stead of 3 pounds.
Plot 10. The treatment this plot received was very similar to
that received by plot 6. The standard fertilizer was used in the
spring and fall. For the summer application nitrate of soda was
used instead of sulphate of ammonia in the fertilizer.
Plot 11. This plot received the same fertilizer treatment as
plot 1. In addition, air-slaked lime was applied at the rate of
1 ton per acre once each year one month after the summer appli-
cation of fertilizer.
Until the beginning of the fiscal year the experiment was not
included as Adams Project work. At this time it was found that
the experiment could be carried thru under favorable conditions.
It was therefore included as project work, and a close study has
been made of the trees during the further development of the
experiment. The experiment has now been under way nearly
three years, and it is hoped the cooperation will continue for at
least two years more.
In general there has been very little change in the condition of
the fruit thus far. Several years are probably required for the
influence of the soil treatment previous to the starting of the
,experiment to become dissipated.
The cold of February, 1917, was a disturbing factor in the
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Florida Agricu4tural Experiment Station
continuity of the experiment. At that time a large percentage
of the fruit was frozen, altho the trees were not seriously injured.
INFLUENCE OF DIFFERENT RATIOS OF PHOSPHORIC ACID AND POT-
ASH IN FERTILIZERS UPON GROWTH AND FRUIT PRODUCTION
IN CITRUS.
Other field experiments which were originally started as ob-
servation experiments, are being carried out in cooperation with
Mr. L. R. Woods of Tampa, Fla., in a grove near Sutherland,
Fla., and another near Tampa, Fla. These experiments were
begun in 1915 for the purpose of observing the effect of different
ratios of phosphoric acid and potash in fertilizers upon the
growth and fruit production of citrus trees.
The following ratios of phosphoric acid and potash have been
included in the fertilizers used in the experiment:
6%' phosphoric acid to 6"% potash
2' phosphoric acid to 6% potash
12'% phosphoric acid to 6er potash
6% phosphoric acid to 2%' potash
6% phosphoric acid to 12% potash
The same sources of phosphoric acid and potash have thus far
been used in making up this fertilizer. They are steamed bone,
dissolved bone black and high-grade sulphate of potash. The
kind and amounts of ammonia are uniform for all plots.
The experiments are being carried out with grapefruit of
unknown variety and with Parson Brown, Pineapple and Tardiff
oranges in a grove near Sutherland, and with seedling oranges
in a grove near Tampa. The trees in the Sutherland grove are
more than eight years old and those in the Tampa grove more
than twenty-five years old.
Thus far the trees show no marked difference from the fer-
tilizer treatments. The cold of February, 1917, froze the fruit
but did not injure the trees badly in the Sutherland grove. The
fruit in the Tampa grove was picked before the freeze. The trees
in this grove were partly defoliated, and those affected with foot-
rot were badly injured.
EFFICIENCY OF FINELY GROUND PHOSPHATE ROCK, STABLE MA-
NURE AND LEGUMES AS A FERTILIZER FOR CITRUS
This field experiment was started in 1916 at St. Leo, Fla., in
the grove of Dr. J. F. Corrigan in cooperation with F. M. Leon-
ard & Co. of Boston, Mass.
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Annual Report, 1917 51R
It consists of thirteen plots in which the phosphate rock, stable
manure and legumes are used alone and in combination, and
with acid phosphate substituted for the phosphate rock in some
plots, and mineral ammonia for the legumes in other cases. The
plots are given uniform potash treatment at irregular intervals.
The trees are Tardiff and Mandarin orange trees on sour stock
and are more than 15 years old.
The experiment has not been continued a sufficient length of
time to expect results.
Respectfully,
B. F. FLOYD,
Plant Physiologist.
Florida Agricultural Experiment Station
REPORT OF ENTOMOLOGIST
P. H. Rolfs, Director.
SIR: I submit the following report of the Entomologist for
the fiscal year ending June 30, 1917.
VELVET-BEAN CATERPILLAR
(Anticarsia gemmatilis)
Studies of the life history, annual migrations, enemies, and
food preferences of this insect were continued. Results of this
work have been gathered into manuscript for a bulletin on the
life history of the insect, and need not be repeated here.
Peanuts have been added to the list of possible food plants of
the insect. A report from the Extension Division stated that
the caterpillars, after consuming a field of velvet beans, will
attack peanuts in an adjacent field. To test this statement, some
experiments were made to determine the ability of the cater-
pillars to live on the peanut plant. It was found that caterpillars
taken in any instar could be raised to maturity on peanut leaves
only, but if offered a choice of peanuts or velvet beans they
invariably chose the beans. When shut in a-cage with peanut
leaves only, the moths laid a few eggs on them, as they will on
other objects if no velvet beans are available. The writer has
not observed that moths in the open fields will lay eggs on
peanuts.
Here, then, is the interesting case of a plant that does not
stimulate the egg-laying instincts of the moth, yet which is a
good and sufficient food for the caterpillars. Under these cir-
cumstances it will be only in fields adjacent to velvet beans that
peanuts will be attacked and then only when the leaves of the
beans have been entirely consumed. This offers an additional
reason for controlling the caterpillars while they are still feed-
ing on the velvet beans.
The moths appeared at Gainesville considerably earlier than
in previous years. On July 20, 1916, not only moths but also
caterpillars in the fourth instar were found on the Station
grounds. The first moths must, therefore, have arrived early
in July. In spite of this early arrival their numbers did not
reach serious proportions any earlier than usual; which is late
in August.
Mr. R. N. Wilson, county demonstration agent for Palm Beach
County, reports that the caterpillars were noticeable in that part
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Annual Report, 1917
of the State by the middle of May, 1917. To date, however, they
have done no serious damage.
It is a peculiar fact that the caterpillars do not seem to be
much, if any, more destructive in the extreme southern part of
the State than in Alachua County, in spite of the fact that in
the former region they arrive months earlier. A possible ex-
planation is that "cholera" begins earlier also. On the other
hand, the caterpillars are much less destructive in western
Florida and southern- Georgia than in the middle counties of
Florida.
CONTROL MEASURES
As stated in previous reports, in the Station fields where the
vines run over the ground without support and therefore are
easily reached with a spray wagon, these caterpillars have been
controlled each season by a single spraying with lead arsenate.
Under cultural conditions as they exist on the average farm
where velvet beans are commonly planted in corn fields, spraying
is out of the question. These conditions led to the trial of
dusting the lead arsenate onto the beans, as recorded in Bulletin
125, the arsenate being applied either undiluted or mixed with
thoroly air-slaked lime. On the Station farm, with careful and
well-trained laborers, the old bag-and-pole method of applying
the dust was quite satisfactory and efficient; but when tried
under ordinary farm conditions, where the beans were planted
in corn fields and the laborers were less careful, the method did
not prove as satisfactory. The plunging of the mules thru the
vines and the carelessness of the laborers resulted in a very
uneven distribution of the poison. As a result, many of the
caterpillars, which invariably drop to the ground when the vines
are disturbed, returned to those leaves which had received little
or no dust, and escaped the poison.
Dusting machines were tried this year. These gave a much
more uniform distribution of the dust and a much better control.
In a corn field where velvet beans were growing under ordinary
farm conditions the caterpillars were effectively controlled for
the season with a single dusting. The control was fully as good
as that ordinarily obtained with a single spraying, and at much
less cost per acre. Much trouble was experienced with the hand
dusting machines which were too delicate for this work.
CONTROL OF NEMATODES
The work of controlling root-knot nematodes (Fla. Agr. Exp.
Sta. Ann. Rep. 1916, p. 55R) has been continued and a bulletin
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Florida Agricultural Experiment Station
issued (Bulletin 136) covering the more practical results of the
cyanamid method and giving such details as are essential to the
person applying the cyanamid. This information will not be
repeated here except insofar as further investigation has modi-
fied or strengthened the results given in that publication.
The work has been chiefly with cyanamid as the vermicide,
and has included the following lines of investigation: (1) The
minimum dose to secure reasonably effective eradication; (2)
the method of application, especially with reference to the
amount of moisture in the soil; (3) the time that should elapse
between the treatment of the land and planting; and (4) the
fertilizing value of the cyanamid. The last point has been con-
sidered incidentally as it is an important factor in the cost of
the method.
AMOUNT REQUIRED
Experience since Bulletin 136 was written serves to emphasize
the importance of the conclusions stated therein that the amount
of cyanamid necessary to apply will vary greatly with the char-
acter of the soil and the manner in which it is handled. The
nematodes have not been completely eradicated from any of the
field plots at Gainesville. On a hundredth-acre plot which was
treated with three tons of cyanamid per acre on October 27, there
are still some nematodes, many more than on any of the Sanford
plots that received only one ton per acre in August. The soil
was dry at the end of October and altho it was irrigated with a
hose the wetting was not nearly as thoro as that the Sanford
plots received. Once our soil becomes thoroly dry, pockets of
dry sand in it are very hard to reach with water applied thru a
hose.
On plots receiving such large amounts of cyanamid, crops
planted as late as three months after the application was made,
were severely damaged. It will probably be found unprofitable
under ordinary circumstances to use more than a ton per acre
for vermicidal purposes. That amount is about all that can be
profitably used as a fertilizer and, if properly applied, it should
reduce the nematodes to such small numbers as to make possible
the growing of susceptible truck crops on the land for a season.
To attempt complete eradication by the cyanamid method is
expensive and the effects on the land of doses in excess of 3,000
pounds are undesirable. Furthermore, under farm conditions a
tract even if completely freed is liable to be at once reinfested
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Annual Report, 1917
thru soil carried on tools, horses' feet, or the shoes of the work-
men. It would seem that the greatest value in the use of the
material will be to control nematodes rather than to eradicate
them completely.
METHOD OF APPLICATION
The method of applying cyanamid has been treated in Bulletin
136 and it is necessary to add only that further trials have
emphasized the necessity for a thoro irrigation following the
application. Work on the Station plots has been handicapped by
the lack of an irrigation system. Watering the plots with a
garden hose is slow and unsatisfactory. An irrigation system is
being installed by means of which the treatment can be made in
a manner similar to that which will be employed by a majority
of the truckers who will use the cyanamid method for combating
nematodes. This method will appeal only to those practicing the
most intensive cropping on high-priced land, and most of such
truckers are supplied with an irrigation plant. The methods
used here will then more nearly approach those of commercial
truckers and the results will be of more value to them.
In all of the experiments reported here the method of applying
the cyanamid is the same as that outlined in Bulletin 136, pp.
154-157.
TIME BETWEEN TREATMENT AND PLANTING
The time between treating the soil and planting varies with
(a) the method of application; (b) the weather, and especially
the soil moisture; (c) the dose; and (d) with the crop to be
planted. With these four factors subject to variation the num-
ber of possible combinations of them is so great that it would be
impracticable to attempt to investigate each factor in its re-
lationship to the others under all possible conditions. Hence,
investigations in the time available were limited (a) to the
method of application which has been found most effective; (b)
to variations in soil moisture ordinarily encountered in truck
gardens; (c) to doses found to be effective in the control of root-
knot; and (d) to those susceptible crops which are generally
planted by truckers at the same season of the year when the
Station plots were planted. Even when thus limited the field for
investigation is so large that only a small portion of it has been
covered and the results must be considered provisional only, until
they can be verified by further trials.
55R
TABLE 24.-ErEcr ON CROPS Or Son. TREATED WITH CYANAMID TO CONTROL NEMATODES
Maximum time after which damage occurred Minimum time with no damage
Dose Severity Dose I
Crop in Days of Date of Moistare in Days Date Moisture
pounds damage Planting Conditions pounds Conditions
Cantaloupe 8000 49 killed March dry
6000 14 killed March dry4000 14 March
2000 30 slight March dry 3000 14 March dry
3000 120 little March very dry
Beans 5000 120 March dry
2000 14 August wet
Celery 4000 80 August wet
Cabbage, collards 1500 7 much January dry 4000 80 October medium
800 7 December medium
Cowpeas 8000 49 severe March dry
8000 66 slight March dry
6000 14 severe March dry
6000 66 slight March dry
4000 14 slight March dry 4000 66 March dry
3000 14 slight March dry
4000 20 severe Tuly moist 4000 160 July wet
3000 21 severe Tuly moist 1000 14 March dry
2000 14 slight March dry 2000 60 July wet
1500 20 severe July moist 1500 50 July moist
1000 20 slight July wet 1000 40 July wet
800 21 trifle Tuly moist 800 30 July moist
Cucumbers 2000 140 little February dry 2000 170 March dry
Beets 4000 24 little November medium 3000 24 November medium
Lettuce 8000 60 November dry
2000 30 November medium
1500 7 killed November medium 1500 60 November dry
1000 40 November dry
800 7 slight Februar y 800 7. December moist
Okra 8000 49 killed March dry
6000 49 killed March dry
4000 14 slight March dry 4000 14 March moist
3000 14 slight March dry
Parsnips
Peas, English
Peppers
Potatoes, Irish
Pumpkin
Radishes
Rape
Roselle
Tomatoes
(plants set out)
Turnips
Watermelons
4000 110
4000 60
0000 50
6000 110
5000 110
5000 50
3000 24
2000 60
1500 30
1000 7
800 7
2000 7
1000 7
800 7
8000 14
4000 12
stunted
severe
much
slight
slight
little
slight
considerable
considerable
considerable
considerable
severe
much
much
much
slight
slight
slight
slight
killed
badly
serious
serious
slight
severe
October
February
November
October
October
November
November
February
February
February
February
March
February
February
March
November
December
November
December
iM arch
iMarch
March
SMarch
April
April
1500
4000
800
dry
dry
medium
medium
dry
medium
'medium
dry
dry
dry
dry
moist
jdry
dry
dry
medium
dry
medium
dry
medium
medium
medium
medium
very dry
dry
3000 24
4000 80
3000 60
2000 60
1500 40
1000 30
800 14
2000 35
1000 7
4000 80
1000 14
3000 14
3000 24
1500 7
800 7
1500 14
4000 24
2000 10
800 14
5000 I 75
1000 7
3000 100
2000 40
2000 120
1500 1 14
800 7
2000 1 35
November
February
February
February
February
February
february
March
March
February
March
December
November
December
December
December
November
November
December
!October
March
March
March
April
'December
December
April
medium
dry
moist
med ium
dry
dry
dry
moist
moist
dry
dry
moist
dry
moist
medium
dry
medium
medium
dry
medium
moist
dry
dry
dry
medium
medium
very dry
8000 14
4000 14
3000 30
2000 7
2000 120
2000 7
Florida Agricultural Experiment Station
In table 24 is recorded under each crop and dose used, the
maximum ime after treatment when damage was noticed, and
also the minimum time after planting in which plants escaped
damage.
PERSISTENCE OF THE MATERIAL
In considering the cost of the treatment the question as to
how long after treatment the fertilizing effects of the material
on plant growth can be seen, is pertinent. In most cases where
a ton or more per acre was used the stimulating effects on plants
could be noticed for approximately a year.
TIME OF TREATMENT
Considerable evidence is accumulating to indicate that winter
treatments of the soil are not nearly so effective as summer or
early fall treatments. This, if true, may be due to the com-
parative dryness of the soil during winter, or to the fact that
the eggs of nematodes are apt to remain unhatched in the soil
thruout the winter and thus escape destruction by the cyanamid.
Further experiments to test this point are in progress.
EFFECTS OF FALLOWING
On October 27, 1916, a number of plots were plowed up and
disked, and at frequent intervals in the winter were disked again
so that they were kept comparatively free from weeds.
These plots were again plowed on March 21, 1917, and some
of them treated with cyanamid; others were left for checks.
Even on the check plots there are decidedly fewer nematodes
than on adjoining plots that were kept in truck all winter. It is
well known that if given the proper conditions of moisture and
temperature nematode eggs will hatch in a few days if the soil
is properly aerated. This would perhaps be a quicker and more
thoro method of starving out nematodes than growing a crop of
non-susceptible plants which will, unless unusual care is taken,
hide some weeds that are hosts to nematodes. Further experi-
ments are planned to determine this point.
IMPORTATION OF BENEFICIAL INSECTS
Thru cooperation with the California State Insectary, two in-
sects that promise to be of importance in combating noxious ones
on citrus have been introduced. The first is the Sicilian mealy-
buy parasite (Paraleptomastix abnormis). The other is a lady-
beetle, Delphastus catalinae.
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Annual Report, 1917
The Sicilian mealy-bug parasite is, as its name implies, a
native of the Mediterranean region but which has become estab-
lished in California where it is accomplishing much good in
holding the mealy-bugs in check. In the first shipments the
insects were all dead upon arrival but later shipments were
brought in successfully on lemons infested with parasitized
mealy-bugs. The parasites were kept breeding in the laboratory
for months on mealy-bugs on potato sprouts. Colonies were sent
to several dozen different localities in the State. It is yet too
early to say whether or not the parasite has become established
in Florida.
This parasite is a minute wasp-like insect. Its wings, which
are held up over the back, are marked with dark bands across
them.
Delphastus catalinae, the lady-beetle, may be valuable as an
enemy of the citrus whitefly. The beetle feeds on a whitefly
native to California and it seemed possible that it might feed
also on the citrus whitefly. Accordingly a colony of twelve was
imported. The individuals at once ate greedily of the eggs of the
citrus whitefly, and more sparingly of the larvae. These beetles
were confined for several weeks during which time eggs were laid
and larvae reared to maturity, thus showing that the beetles can
complete their development on this new food.
Unsatisfactory conditions in the cages, particularly that of
moisture, and the difficulty experienced in transferring the
beetles to fresh food without losing them, finally resulted in their
being liberated in the insectary where they maintained them-
selves for several months. None has been seen for several
months, however, and it seems probable that the colony has died
out. We expect to secure other colonies this summer and to
liberate some of them in groves where conditions are more nearly
normal.
INSECTS OF THE YEAR
PLANT-BUGS
The larger plant-bugs, and especially the green soldier-bug or
"pumpkin bug" (Nezara viridula), were unusually abundant in
1916, not only in Florida but, according to Dr. E. W. Hinds,
entomologist to the Alabama experiment station, in southern
Alabama as well.
ON CITRUS
Many complaints of damage done to citrus by plant-bugs were
received in October and November. Plant-bugs attack the young
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Florida Agricultural Experiment Station
shoots of the trees often causing them to wilt and die. In young
groves they often do considerable damage in this way during
the summer. On large trees the damage is negligible. It is the
fruit that sustains the most severe damage. This turns yellow
around the punctures which, if sufficiently numerous, cause the
fruit to fall. These fruits are dry and tasteless, the juice having
been withdrawn by the bugs. Tangerines are most severely
attacked; oranges are a second choice, while grapefruit are not
much troubled.
Plant-bugs were very numerous in Lake County in October.
Some growers attempted to kill them with sprays. One used a
solution of 10 pounds whale-oil soap and % pint black leaf 40
in 50 gallons of water. This killed the nymphs but not the adults.
The adults were often benumbed and lay motionless for a few
minutes, but in every case observed they ultimately recovered.
Another grower used the common whitefly oil emulsion to which
was added not only black leaf 40 in the proportion of 1 part to
1000, but 1 percent of carbolineum as well, with the same un-
satisfactory results.
Collecting the bugs seemed to be the only remedy. Previous
experience in collecting bugs on potatoes led to the opinion that
this method would be feasible in a citrus grove. But grove man-
agers have uniformly believed the cost of the method to be
prohibitive. Because of this general belief the cost of collecting
the bugs from a 200-acre grove is given.
Fruit on trees at Winter Haven was being severely damaged
by plant-bugs early in November. The trees were about ten
years old, set 20 by 30 feet, and bore a light crop of fruit. The
average number of bugs to a tree varied from thirty in some
parts of the grove to a hundred in other parts; 97 percent of
them were Nezara viridula, the green soldier-bug commonly
known in Florida as the "pumpkin bug." The grayish-brown
stink-bug (Pentatoma punctipes) made up about 2 percent of
the number; the remaining 1 percent consisted chiefly of the leaf-
footed plant-bug (Leptoglossus phyllopus), altho there was a
sprinkling of cotton stainers among them.
As is usually the case where plant-bugs damage a citrus grove,
the attack had been made possible by improper management of
the leguminous cover crop on which the bugs breed. This crop,
beggarweed, had been cut from the middles between the rows
of trees but not from between the trees in the rows. This pro-
cedure had driven the nymphs toward the trees, and when the
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Annual Report, 1917
beggarweed had matured and become unattractive the adults
and remaining nymphs had readily climbed onto the lower
branches of the trees from the beggarweed. This method of
cutting the cover crop had been followed for several years with
no harmful results, and there would probably have been no
Fig. 1.-Net used for collecting pumpkin bugs from citrus trees
trouble this year had not the bugs been more numerous than
usual. The better method is to cut the beggarweed from around
the trees first, using a scythe, and to leave the middles to be cut
later, but not later than September 15. This will work the
nymphs away from the trees which, after the middles are cut,
can be reached only by climbing the trunk or those limbs that
touch the ground.
The method employed in collecting the bugs was a modification
of that formerly used in collecting the curculio from plum and
peach trees. Large, shallow nets for the purpose were made of
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Florida Agricultural Experiment Station
muslin. These were three feet in diameter (four or five feet is
belter) and of equal depth. They had short handles extending
across the diameter of the nets to stiffen the rim made of
telephone wire. (Fig. 1.) One man can manipulate such a net
but two men can cover the ground more rapidly. One holds
the net under a limb and the other gives the limb a quick, vigor-
ous shake. The bugs roll into the bottom of the net. After the
men have finished a tree the bottom of the net is dipped into a
bucket containing kerosene. This keeps the net constantly wet.
By using these nets in the foregoing grove the bugs were
collected at a cost of between 50 cents and 75 cents an acre.
Two men with a net covered at least four acres a day. The men
were paid $1.50 a day. This cost is less than that of spraying
even if a mixture that would kill the bugs could be used. On
larger trees with more bugs the cost would be greater but in few
cases should exceed $1.50 an acre, still less than the cost of
spraying.
For use under large trees with branches not touching the
ground, the nets should be larger. Some nets 6 by 12 feet in
size were used. These were made by suspending canvas from a
light wooden frame similar to a quilting frame, permitting the
fabric to sag two or three feet in the center. A closely woven
canvas should be used so that insecticide oil or kerosene can be
retained in the bottom of the net to kill the bugs which roll into
it. The longer pieces of the frame projected 18 inches beyond
the net and served as handles. Two men will be needed to carry
this net and a third one to shake the tree. It is better to use
the nets in twos, one on either side of the tree, so that the whole
tree can be shaken at one time. These large nets could not be
used at a temperature much above 70 degrees as the bugs will
fly before striking them. Their use is therefore restricted to
cold days, to very early mornings, or to moonlight nights. Even
with the smaller nets it is better to work in the early morning
when the bugs are sluggish.
ON POTATOES
The hand collecting method has been used for plant-bugs on
potatoes, tomatoes and sunflowers. The adults of Nezara viri-
dula and also the much larger, dark brown, club-legged plant-
bug, Acanthocephala femorata, attack these plants severely in
the early spring when coming out of hibernation. The attacks
are specially severe when the- crops are growing near hammocks,
which afford good shelter for hibernation. Collecting is best
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Annual Report, 1917
done with a wide-mouthed dish or pan provided with a handle
to obviate stooping. With a short stick the collector knocks the
bugs into the vessel containing a little kerosene. A man can
easily cover an acre in an hour. The collecting is best done in
the heat of the afternoon when the drooping vines will enable
one to find the bugs readily. It was found necessary to cover the
field only two or three times in the season to control these bugs.
Apparently after they once reach desirable plants they move
about but little unless disturbed.
Because of its size, the plant-bug most destructive to the
potato plant is the club-legged plant-bug. This species, and to a
less degree, the leaf-footed plant-bug, shows a decided preference
for sunflowers over any cultivated plant under observation.
Advantage was taken of this fact this year and sunflowers were
planted as a trap crop about a patch of early potatoes. The
experiment was a success. Not one bug was seen on the po-
tatoes, while the sunflowers were heavily infested and some were
killed. The sunflowers should be planted as early as possible in
order that they may be large and attractive during the growing
period of the potatoes. As the young seedlings will withstand a
light frost, sunflowers may be planted nearly as early as potatoes.
If one wishes to produce a good crop of sunflowers he should
collect the bugs. This will be much easier than to collect them
from the entire potato field.
NOTES ON OTHER INSECTS
On October 23, the pecan twig-girdler (Oncideres cingulata)
was received from Tiger Bay where it had been girdling Euca-
lyptus rostrata. This seems to be a hitherto unrecorded host
plant of this beetle.
The sweet-potato root-weevil (Cylas formicarius) was re-
ceived from Baker County where the infestation was severe.
This being a highly destructive pest a warning press bulletin
was issued by the Experiment Station, and the problem of con-
trol referred to the State Plant Board.
On November 24, the entomologist had the unusual experience
of being stabbed by a "pumpkin bug" (Nezara viridula). There
seems to be no previous record of this insect attacking man. The
wound was painful for a few minutes only. A discolored bluish
area resulted, which by the next morning was but a red pimple.
The day was cool and the bug sluggish.
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Florida Agricultural Experiment Station
In late March and early April many complaints were received
of damage to tomatoes and beans by the large leaf-hopper (Stic-
tocephala inermis).
On April 27, the cactus weevil (Gerstaeckeria hubbardi, Lee.)
was received from Jennings where it was reported to be attack-
ing cotton.
In late April and early May much damage to cotton by the
Scarabaeid beetle (Strigoderma pygmeae) was reported from
Bradford County.
Wireworms were destructive to cucumbers about Morriston
during the latter part of April.
The greenhouse thrips (Heterothrips haemorrhoidalis) has
been unusually destructive to many ornamentals out of doors. At
Gainesville it was very abundant on coleus, which it was killing.
At Estero it defoliated and killed many croton plants. At Winter
Haven it was especially abundant on Japonica.
In May, the chicken tick (Argas miniatus) was received from
the county demonstration agent of Seminole County, who re-
ported it as doing much damage in at least one flock of chickens.
Hitherto, this pest has been reported only from Ft. Lauderdale
and Key West.
The striped blister-beetle (Epicauta vittata) severely damaged
peppers at Rocky Point, near Gainesville, in June. They fed
some on the leaves of the plants, but their chief point of attack
was the upper surface of the fruit near the stem. Here they
often ate thru the walls and, reaching the interior, fed on the
immature seeds and placentae. They were being eagerly at-
tacked by a large robber fly not yet identified. Blister-beetles
are reported as being very abundant in many places in the Gulf
States.
The 12-spotted Diabrotica, the adult of the southern corn root-
worm, was very abundant during the early part of winter in
West Florida. At Pace, it destroyed satsumas, onions, and some
other crops.
In early August, 1916, the woolly whitefly (Aleurothrizus how-
ardii) was somewhat in evidence on Merritt's Island. This pe-
riod of the year had not been well-covered in previous studies.
The date of the emergence of the July-August brood as given in
Bulletin 126, p. 90, was based largely on estimates. A trip to
the Island served to establish the substantial correctness of the
date given. The parasite, Eretmocerus haldemani, was seen to
be getting the whitefly under control. There is very little evi-
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Annual Report, 1917
65R
dence of this whitefly on the Island at present, altho there are a
few mild outbreaks on the mainland opposite the south end of
the Island.
Respectfully,
J. R. WATSON,
Entomologist.
Florida Agricultural Experiment Station
REPORT OF PLANT PATHOLOGIST
P. H. Rolfs, Director.
SIR: I submit the following report of the Plant Pathologist
for the fiscal year ending June 30, 1917.
There has been no material change in the plans of the depart-
ment from the previous year and certain progress has been made
in all lines of investigation.
CITrrUS DISEASES
GUMMOSIS
Gummosis has again been the major problem for the year and
the same plan of investigation has been followed as that of
previous seasons. Results obtained agree mainly with those of
previous years and definite conclusions cannot yet be drawn re-
garding the primary cause of this disease.
There are certain features of the disease which strongly
suggest that it might be parasitic in origin; however, all at-
tempts thus far to reproduce the disease in healthy citrus bark
thru inoculations and contact with infected tissue have resulted
in negative or conflicting results.
Certain species of fungi are commonly associated with gum-
mosis, especially in advanced stages of the disease, and some
appear to be more or less constant in association; however, no
specific fungus has yet been found that when introduced into
healthy tissue will produce the characteristic symptoms of the
disease.
Two series of inoculation experiments have been completed
this season in which diseased bark tissue from active gummosis
areas was used as an inoculum. The inoculations were made into
healthy bark of grapefruit and orange trees.
Twenty-seven inoculations were made in the bark of a grape-
fruit tree, including thirteen checks. In the check inoculations
healthy bark tissue was introduced. The results obtained from
this series are not dependable since typical cases of the disease
appeared in the checks as well as in some of the inoculations
where diseased bark was introduced. It was also noted that
several characteristic gummosis areas developed naturally on
the trunk of this tree during the period of the experiment. Some
of these were in close proximity to the checks and inoculations
but in no way connected with them.
Ten inoculations, including five checks, were made into the
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Annual Report, 1917
healthy bark of an orange tree following the same method as
used in the inoculations into the grapefruit tree. These inocula-
tions all healed without showing the slightest symptoms of gum-
mosis. Characteristic gummosis areas developed naturally on
the trunk of this tree during the period of the experiment, but
at some distance from the points of inoculation.
ASSOCIATED ORGANISMS
Some study has been made of the organisms associated with
gummosis areas. Cultures have been taken in the field from
areas representing various stages in the development of the
disease, from the first visible indications to well advanced stages
of gummosis. In taking such cultures efforts were made to
avoid as far as possible such contaminations as would likely
occur where cultures are made in the open field. A special
forceps was designed whereby a small core or cylinder could be
cut from the bark of the tree and transferred to culture tubes
with little or no exposure to outside contamination. This method
has proved very successful in taking cultures from the bark of
trees in the open, and thru its use outside contamination has
been largely avoided.
In taking cultures from gummosis areas the surface of the
bark at the edge of the diseased and healthy tissue was first cut
away with a flamed scalpel. A small cylinder of tissue, 1 to
2 mm. in diameter was cut out at this point with the forceps and
transferred directly to slanted agar tubes. These were later
transferred to agar plates in the laboratory and the resultant
bacterial and fungus growths identified as far as possible. From
the earliest recognizable stages of the disease usually no fungus
or bacterial growth was obtained. From the more advanced
stages of the disease several species of fungi and bacteria have
been isolated. Phomops's citri has appeared more constantly
in these cultures. Diplodia natalensis and several Fusaria have
been frequently isolated and occasionally other species of sapro-
phytic fungi that no attempt was made to identify. Species of
bacteria isolated from such cultures have been varied and no one
species has been obtained with any degree of constancy. Such
organisms have been discarded as having no bearing on the
cause of the disease.
The frequency with which Phomopsis citri has occurred in
these cultures may lead one to suggest that this fungus might
be a probable cause of the disease. Its association may be ex-
plained on other grounds, however, and the data at hand does
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Florida Agricultural Experiment Station
not indicate that this fungus is the primary cause of gummosis,
altho it may be a secondary factor in the development of the
disease. The fungus is a weak parasite and best adapted to
growth in dead or weakened tissue. It is generally distributed
and abundantly present in citrus trees. The cracked and open
condition of gummosis areas, with the broken down bark tissue
would afford a favored habitat for the fungus. On several occa-
sions the writer has introduced this fungus from pure cultures
into healthy citrus bark and in all cases these inoculations soon
healed without showing any suggestions of gummosis.
It seems evident, however, that Phomopsis, Diplodia and prob-
ably other species of fungi are responsible for the gradual en-
largement and aggravated condition of gummosis areas.
CONTROL EXPERIMENTS
Control experiments at Weirsdale were continued this season
on the same plan as followed in the previous season. The results
have been about the same as those of the preceding year. A
complete report of this experiment will be given at a future date.
MELANOSE
The pruning experiments for the control of melanose have
been continued for the fifth season. The data obtained from
checking over the 1916 crop do not differ materially from that of
past seasons, especially in regard to the block that has been
pruned consistently each year. The poor showing made for
blocks 2, 3 and 3* in the report of the 1916 crop may be ex-
plained in parf by the fact that these trees had not been pruned
for eighteen months previous to this date and a considerable
amount of dead wood was present in which the fungus had de-
veloped abundantly. Thus the fruit on these trees had been ex-
posed to a much larger amount of infectious material than was
present in block 4.
In table 25 is given the record of each season's crop since the
experiment was begun, showing the percentage of the different
grades of fruit, date pruned, etc.
While it has not been possible to avoid melanose injury entirely
by the most careful pruning, yet the percentage of bright fruit
has been greatly increased over that of the check plots. Even
where the pruning has been made by ordinary laborers a large
increase in bright fruits has been obtained. A great improve-
ment has also been noted in the fruits classed as seconds, over
the same grade from the check plots, which does not show in the
tables.
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Annual Report, 1917
TABLE 25.-RESULTS OF PRUNINGS TO CONTROL MELANOSE
Record of 1913 Crop
Block
No. 1
No. 2
No. 3
No. 3*
No. 4
No. 1
No. 2
No. 3
No. 3*
No. 4
No. of
trees
No. 1 12
No. 2 16
No. 3 8
No. 3* 8
No. 4 12
No. 1
No. 2
No. 3
No. 3*
No. 4
When
Pruned
Check
Jan. & June
Jan.
Jan.
June
SPercentage of
SBrights
23
47
40
56
34
Record of 1914 Crop
Check 12
Jan. & June 35
Jan. 34
Jan. 56
June 45
Record of 1915 Crop
Check 0
.........-.........-----.......... 2
......-- ....... ...-........ 4
June 31
Record of 1916 Crop
Check 5
June 22
June 18
June 19
June 34
I Seconds Russets
74 3
52 1
57 3
43 1
62 4
73 15
60 5
63 3
41 3
53 2
67 28
63 15
70 15
72 9
62 4
*Carefully pruned.
It is probable that the use of some fungicide in connection with
the pruning would further reduce the percentage of the melanose
injury.
CITRUS CANKER
Only-minor studies have been given to citrus canker in the last
season. The soil cultures mentioned in last year's report have
been kept under observation and tested from time to time.
A test was made of one of these soil cultures seventeen months
after Pseudomonas citri had been introduced. Living organisms
were obtained that proved to be Ps. citri. At the time of this
test the soil was thoroly air-dry and would pour like sand. The
culture had not been moistened since it was inoculated and the
organisms had survived the greater part of this period in the
dry soil.
Some of the dry soil from this culture was applied to tender
citrus foliage, at the same time the foregoing test was made.
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Florida Agricultural Experiment Station
The foliage was moistened and kept in a moist condition for
three or four days. A heavy infection of canker developed on
the foliage thus treated.
A recent test of another culture from this same series was
made twenty-six months after Ps. citri had been introduced.
This culture had been tested on previous occasions and Ps. citri
was repeatedly isolated in such tests. The culture had been
twice remoistened with sterilized water since it was first inocu-
lated. Ps. citri was isolated in the test made twenty-six months
after this culture was first inoculated. Soil from this same cul-
ture applied to young citrus foliage at the time the foregoing
test was made produced a heavy development of citrus canker on
the foliage thus treated.
The results from these cultures indicate that Ps. citri can
propagate and remain alive and virulent when kept in soil for a
period of twenty-six months, and that the organisms are capable
of surviving long periods of dessication without complete loss of
vitality and with little apparent loss of virulence.
FOOT ROT
In connection with the study of the gumming of citrus trees
a fungus was isolated from a typical case of foot rot or Mal di
Gomma, in March, 1916. At first this fungus was believed to be
Pythiacystis citrophthora, Sm. & Sm., a fungus reported from
California as the cause of the brown rot of lemons, and a type
of gummosis common in citrus trees in that state. In the Annual
Report for 1916, p. 78R, mention was made of the fungus isolated
from foot rot of citrus trees, and it was suggested that this
fungus under study was probably Pyth. citrophthora. The pre-
liminary study and data at hand at that time seemed to indicate
as much. Further study of the fungus isolated from active cases
of foot rot of citrus trees showed certain cultural differences
from that of Pyth. citrophthora obtained from California. It
was later learned that our fungus attacked other hosts than
citrus and showed certain morphological characters not reported
of Pyth. citrophthora.
In 1915, C. D. Sherbakoff, Associate Plant Pathologist, isolated
a fungus from a tomato fruit rot which proved to be an unde-
scribed species. This fungus was later described as Phytoph-
thora terrestria, n. sp., and reported to be the cause of buckeye
rot of tomato fruits.(')
(1) Sherbakoff, C. D., Buckeye Rot of Tomato Fruits, Phytopathology,
VoL 7, pp. 119-129, 1917.
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Annual Report, 1917
In working with these fungi in the laboratory, a similarity in
cultural habits was soon noted between the fungus isolated from
foot rot of citrus trees and the one isolated from the tomato
fruit rot. A further comparative study of the two showed them
to be identical morphologically and in cultural characters. Cross
inoculations with these two strains into tomato and lemon fruits
gave identical results. They were found to be identical and the
same species. Hence the fungus isolated from foot rot or Mal
di Gomma of citrus trees will be considered in the future as
Phytophthora terrestrial, Sherbk.
CAUSE
Foot rot or Mal di Gomma are terms usually applied to a
particular disease of the crown and main roots of certain vari-
eties of citrus trees. It is characterized by a decay of the bark
at these points, which usually begins as small irregular patches
at or near the surface of the soil, gradually extending until a
greater part of the crown and roots are involved or the death of
the tree results. More or less gum flow may be present. Swingle
and Webber M have aptly described the disease in their report of
"The Principal Diseases of Citrus Fruits in Florida."
Foot rot is widely distributed and seems to occur in most
countries where citrus fruits are grown. The disease in Florida
is confined chiefly-to trees of the sweet orange and lemon vari-
eties.
The cause of the disease has been a question of doubt even
among those who have made a study of it. A majority perhaps
have considered it parasitic, but no definite species of fungus or
bacterium has been pointed out as being the primary cause of
foot rot. Briosi(2) suggested that a species of Fusarium was
probably the cause of Mal di Gomma or foot rot, but his deduc-
tions seem to be based on the association of this fungus with the
diseased areas. Many have accepted this view and Fusarium
limonis Bri. is frequently quoted as the cause of foot rot or Mal
di Gomma. Our studies the past season, however, indicate that
the foot rot which is common and widely distributed in Florida,
is of fungus origin and is caused by the invasion of Phytoph-
thora terrestrial. The disease is common in the old sweet seed-
ling orange groves thruout the State and becomes more or less
(1) Swingle, W. T., and Webber, H. J., Bul. 8, p. 29. Div. Veg. Physi-
ology and Pathology, U. S. D. A., 1896.
(2) Briosi, G., Intorno al mal di gomma degli agrumi (Fusisporium
limoni Briosi) Atti R. Acad. Lincei (Roma) ser. 3.2: 485-496. 1878.
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Florida Agricultural Experitment Station
active each season. A number of such groves have come under
our observation within the last year.
In cooperation with the State Plant Board a rather extensive
field survey has been made of groves affected with foot rot, rep-
resenting most of the territory included within the citrus belt.
Mr. H. M. McKay, of the State Plant Board, was assigned for
this field work and obtained cultural material in the field from
more than five hundred active cases of foot rot. Small cylinders
of bark tissue were removed from the margins of such areas,
transferred to agar slants and sent to the laboratory. These
were plated in cornmeal agar and the resultant growth observed
and identified as far as possible. About twenty-three hundred
such cultures were made and examined.
Phytophthora terrestrial was repeatedly found in these cultures
and the fungus was isolated from cases of foot rot representing
widely separated areas in the State, indicating a general dis-
tribution.
Pure cultures of the fungus were obtained from active cases
of foot rot from the following localities:
Alva Ft. Meade Palmetto
Arcadia Ft. Myers Plant City
Bartow Hopewell Sarasota
Bee Ridge Kisaimmee Tavares
Bowling Green Knights Weirsdale
Dover Lakeland White City
Eagle Lake Laurel Hill Winter Garden
Eastlake Manatee Winter Park
Having repeatedly obtained the fungus from the affected bark
tissue, attempts were also made to prove the pathogenicity of
the same thru inoculations into healthy citrus bark. Only a few
preliminary inoculations have been made thus far and these
have only been partly successful.
In two series of inoculations positive infections were obtained
by the introduction of pure cultures of this fungus into healthy
citrus bark. In one case, where the tree inoculated was of bear-
ing age, areas developed from the inoculations typical of cases
of foot rot as ordinarily observed in the grove. In a second case
where small citrus trees in pots were inoculated, the bark tissue
was rapidly invaded and broken down, but no definite area re-
sulted. The bark tissue of the entire stem was soon involved and
the tree died.
Two other series of inoculations were made but these gave
negative results. However, these inoculations were made at a
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Annual Report, 1917
time and under conditions less favorable for the development of
foot rot, which may account for the failure.
Further experiments are necessary along this line and under
conditions more nearly approximating that of the grove, in order
to determine the true relationship of the fungus to its host and
its manner of attack.
SOME DISEASES OF THE SEASON
CITRUS
ANTHRACNOSE (CoUetotrichum gloeosporioides Penz.).-This
disease caused some injury to fruits during the late fall and early
winter. Outbreaks appeared to be local and influenced by weather
conditions at the time.
WITHERTIP (Colletotrichum gloeosporioides Penz.).-This dis-
ease caused much inujry to citrus groves in general as an after-
math of the low temperature in February. Weakened trees and
new growth that put out in late spring has been severely attacked
by this disease and drastic pruning has been necessary in many
cases to check it.
SCAB (Cladosporium citri Mass.).-Very little scab has de-
veloped on the foliage and fruit that has come out since the
freeze of February. Where trees badly affected with scab were
completely defoliated and much of the younger wood killed, the
disease has been virtually eliminated from such trees. Occa-
sional specimens of scab on sweet orange varieties have been
called to our attention during the past season. This is of interest
since the sweet orange varieties are considered immune to this
disease.
FRUIT SPOT
This is a new type of fruit injury that has come under observa-
tion within the last two years. Very few specimens have been
received to date and the amount of injury seems to have been
limited in each case, confined to a few fruits only. A few speci-
mens of this trouble were received from Ft. Myers in February,
1916. In February of the present year three specimens were
received from Leesburg, and in June a single specimen of the
same trouble was obtained from near Miami. This spotting has
been observed only on mature grapefruit. At first glance the
disease may easily be mistaken for a form of Anthracnose spot-
ting that is sometimes observed on citrus fruits.
Spots are formed on the surface of the rind from 3 to 10
73R
Florida Agricultural Experiment Station
,,,`
..
r: k5'~~:~
-t!
.. i .~
:f(
~*k~n,. "r
c
Fig. 2.-Fruit spot on grapefruit. Slightly reduced
millimeters in diameter. They are dark brown to nearly black
in color with a smooth, hard, glazed surface. This hard mass of
surface tissue is slightly raised and the surrounding tissue is
sunken at the edges, forming a narrow depressed ring surround-
ing or outlining the spot. (Fig. 2.) Injury seems to be con-
fined to the rind tissue as no penetration or breaking down of
the juice sacks was observed even when specimens were kept for
a number of days in a moist chamber. A decay of the fruit oes
not seem to result.
The cause of the spotting has not yet been determined. A
dark-colored fungus has been isolated from the interior and
from tissue taken at the margins of such spots. This fungus has
appeared more or less constantly in all of the specimens ex-
amined so far. The fungus has not yet been determined since
74R
Annual Report, 1917 75R
it has failed to sporulate in any of our cultures thus far. A
sufficient study has not been made of this fungus to determine
its relationship to the spotting.
PECAN DISEASES
Studies of Pecan Diseases are covered in the report of Mr.
Matz, Laboratory Assistant in Plant Pathology.
Respectfully,
H. E. STEVENS,
Plant Pathologist.
Florida Agricultural Experiment Station
REPORT OF ASSOCIATE PLANT PATHOLOGIST
P. H. Rolfs, Director.
SIR: I submit the following report of the Associate Plant
Pathologist for the fiscal year ending June 30, 1917.
VEGETABLE DISEASES
The work with diseases of vegetables has been conducted this
year as far as practicable along lines followed during the two
preceding years. Chief attention was given to seed-bed diseases,
mainly to damping off. Work on buckeye rot of tomato fruit
and pineapple wilt was continued, and a preliminary study made
of a bacterial spot of peppers of which little is known.
DAMPING OFF IN THE SEED BED
ISOLATIONS OF THE CAUSAL ORGANISMS
The work of isolating the disease-causing organisms from
affected tomato, eggplant, lettuce and celery plants this year
gave results similar to those obtained earlier in the work, and
showed that the fungus, Rhizoctonia solani Kuhn, is the organism
most commonly associated with damping off in the seed bed.
That this fungus is able to cause the disease has already been
proved by other pathologists and by the writer. (Fta. Agr. Exp.
Sta. Ann. Rep. 1916, p. 81R.) Several series of isolations from
the soil in which plants affected with Rhizoctonia were grown
and from a new soil, in certain instances, resulted in obtaining
cultures of the fungus. On some occasions the fungus was
isolated also from eggplant seed disinfected in 1:1000 solution
of corrosive sublimate for ten minutes, and also from seed not
disinfected. From these results it may be concluded that in cer-
tain cases the fungus is present in a new soil and, also, that it is
sometimes introduced into a seed bed with the seed. This, then,
would explain why damping off is sometimes present in seed
beds on a new soil. However, it should be noted here that damp-
ing off is usually much less conspicuous on a new soil than it is
on a soil previously used for seed beds.
CONTROL OF DAMPING OFF
From the greenhouse work of last year on control of damping
off by soil treatment with different chemicals it appeared that of
all substances tested 1/2 percent copper sulphate solution was the
most promising (Fla. Agr. Exp. Sta. Ann. Rep. 1916, p. 83R).
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Annual Report, 1917
In August, 1916, this solution was tried under field conditions
in a cooperative experiment on celery seed beds at Sanford.
Results of the experiment in which the 1/, percent solution of
copper sulphate was applied at the rate of one pint per square
foot indicate that the treatment apparently reduces celery germ-
ination and the rate of plant growth. However, these results
should be considered incon-
clusive mainly because of
the almost total absence of
damping off in all of the
plots, including the check
plots.
A series of experiments
to control damping off was
started on the Station
grounds but the freeze in
February entirely ruined
them. Some work on damp-
ing off control was carried
out on a small scale in the
greenhouse, but the results
did not add any informa-
tion to that previously re-
ported.
PHOMOPSIS OF EGGPLANT
In the last report (Fla.
Agr. Exp. Sta. Ann. Rep.
1916, p. 83R) it was stated
that Phomopsis vexans
(Sacc. & Syd.) Harter had
in some instances been
found to cause damping off Fig. 3.-Eggplant stems affected with
in eggplant seed beds. This tipover
year, the fungus was isolated from eggplant seed obtained in
a local -market. This particular lot of seed showed a com-
paratively high germination percentage and yet the seed was
considerably contaminated with Phomopsis. Seed not dis-
infected showed an average of about 7 percent contam-
ination, and seed disinfected in 1:1000 solution of corrosive sub-
limate for ten minutes showed more than 1 percent. This seems
to prove definitely that the fungus is carried with the seed and
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Florida Agricultural Experiment Station
that contaminated seed should be considered a factor in the dis-
semination of the disease. Some other plant pathologists (for
instance, Home, W. T. Observations on eggplant troubles in
Cuba. Agriculture. Secretaria De Agricultura, Comerice y
Trabajo. Cuba 1:7-11, April, 1917) and the writer (Fla. Agr.
Exp. Sta. Ann. Rep. 1916, p. 86R) had previously only assumed
that such might be the case.
Following up the association of Phomopsis with eggplants in
the field it was found that the fungus causes a disease as yet
undescribed, namely, the tipover or breakover of the plants (fig.
3). Plants affected with this trouble appear to be quite healthy
but with more or less noticeably constricted stems at or near
the level of the ground. At this point they break easily of their
own weight or when blown by the wind, and must be replanted.
Last winter a field was observed in which at least 25 percent of
the plants were affected with tipover. The findings in connec-
tion with the Phomopsis trouble of eggplants are incorporated
in Bulletin 139 of this Station.
BUCKEYE ROT OF TOMATO FRUIT
Buckeye rot of tomato fruit was reported for the first time in
the last Annual Report (pp. 88R-89R). Some additional work
on this disease has been done during the year and the results
obtained, together with previous findings, were published in a
technical paper. (Sherbakoff, C. D. Buckeye rot of tomato
fruit. Phytopath. 7:119-129, figs. 5, 1917.) This paper ends
with a brief summary, as follows:
"1. The buckeye rot of tomato fruit is common in certain
places on the low lands of the east and west coasts of Florida.
2. It occurs only on the fruit that touches or nearly touches
the ground. 3. It is caused by the fungus Phytophthora terres-
tria n. sp., which is also found on other hosts (in diseased bark
of citrus trees affected with foot rot in Florida and Cuba, and
on lupines affected with stem rot). 4. It causes considerable
injury to the fruit in the field and in transit. 5. Staking the
plants in the field and keeping over the picked fruit (from fields
not staked) a few days before it is packed seem to be practical
methods of its control."
Last spring the rot was observed in the field as well as in a
local market and the disease this year seems to have been com-
mon tho not very prominent; probably due to the fact that the
season was comparatively dry.
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Annual Report, 1917
In the Manatee region many tomato fields were staked this
year and the writer had opportunity to observe the effect of
this measure on the prevalence of buckeye rot in one of the fields.
It was observed that only fruits which fell to the ground during
a rain storm a few weeks previously were affected with the rot.
This fact was also noted by the field manager who suggested
that plants knocked to the ground by the storm be examined
for the disease. On such plants it was not difficult to find the
rot, while it was entirely absent on staked plants.
BACTERIAL SPOT OF PEPPER
A bacterial spot has been observed most commonly and in
great abundance on pepper leaves (fig. 4), but in certain in-
stances it was not uncommon also on the fruit (fig. 5), and on
the stems. All the spots are of quite characteristic appearance,
having a more or less rough surface and being somewhat higher
than the surrounding healthy tissues. The color of the spots
varies from a brown to pink-brown, and to a nearly purple-red.
The red hues are often prominent on leaf spots. The fruit spots
are usually much raised and wart-like in appearance. The stem
spots are mostly in the form of irregular, oblong, rough scars.
The size and shape of the spots on leaves and fruit are shown
in figures 4 and 5. Spots on the lower side of the leaf are more
Fig. 4.-Pepper leaves affected with the bacterial spot; the two leaves on
the right show appearance of the spot on upper side, the leaf on the
left shows its appearance on the lower side. The spots are very old
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Florida Agricultural Experiment Station
distinct than those on the upper side, and leaf tissues around the
spots are sometimes much paler than the rest of the leaf.
The disease on pepper leaves was first observed by the writer
in October, 1916, on specimens received from Fort Myers; on the
fruit in November and December of the same year on specimens
from Sanford and Palm Beach County. Specimens from Palm
Beach County showed the spot also on the stems. In this county
the writer had observed the
disease in a few fields in
January, 1917, finding con-
siderable of it on the leaves
and some on the fruit and
stems. Freehand sections of
fresh diseased material
showed in every case that
the diseased parts are full
of certain bacteria; no fun-
gus was found. Poured
plate cultures made in stan-
dard nutrient agar from
spots disinfected in 1:1000
solution of corrosive subli-
mate for ten seconds, gave
invariably only bacterial
colonies; the result being
the same whether the cul-
tures were made from leaf,
fruit or stem spots. In ev-
ery case a certain yellow
bacterium was obtained but
it was very often accompa-
Fig. 5.-Pepper fruit affected with the nied by other bacteria
bacterial spot among which another yel-
low bacterium was most
commonly present. Subcultures of several strains of these two
bacteria were made on standard nutrient agar slants, and kept
for further work.
On March 30, 1917, pure cultures of these bacteria were used
to inoculate pepper plants in the greenhouse. For these inocula-
tions the bacteria were grown in standard nutrient bouillon and
incubated for five days at 250. C. The cultures, half diluted with
sterilized water, were sprayed onto the pepper plants with an
atomizer and the plants were then covered with bell jars for
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Annual Report, 1917
nearly three days. In all, four strains of the supposedly patho-
genic bacteria and two of supposedly saprophitic bacteria were
used in these inoculations, and from two to three plants were
inoculated with each culture. Presuming that one of the bac-
teria would surely prove to be a saprophite, and thus the plants
inoculated with them would serve as checks, no checks as such
were kept.
On April 2, three days after inoculations were made, the inocu-
lated plants were examined. All plants
inoculated with the supposedly patho-
genic bacteria showed more or less nu-
merous spots which in their character
were strongly suggestive of being an
early form of the disease in question.
The spots appeared on the leaves and
on the stems. Since then the spots de-
veloped very slowly on all plants from
which the bell jars were removed; on
those left covered the spots developed
more rapidly.
Figure 6 shows some of the spots as
they appeared April 16. These spots
are of about average size. Figure 7
shows the spots as they appeared June
27. All plants sprayed with the other
bacteria, also kept under bell jars, did
not show any spots.
These inoculations with pure cultures
of the bacteria isolated from fruit, stem
and leaf spots show that the disease is
Fig. 6.-Pepper leaf bac-
caused by the bacteria. Bacteria were trial spots produced by
reisolated from the spots produced by inoculation with pure
the inoculations; the reisolations being t od f t bater inc
made from spots disinfected in 1:1000 tion
solution of corrosive sublimate for ten
seconds and by means of poured plates with standard nutri-
ent agar.
During continuously wet weather the disease seems to spread
rapidly under field conditions, but during dry weather, and in
the Station greenhouse where the soil is watered without any
noticeable moistening of the foliage, the disease does not spread
at all but gradually disappears as the old leaves fall off.
The chief damage caused by the trouble is that of spotting
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the fruit, which renders it unsightly. Under favorable con-
ditions a considerable percentage of the fruit may be thus ren-
dered unmarketable. The injury to the foliage may also be of
importance.
This disease seems to be but little if at all known to the lit-
erature which, excepting one brief mention by Heald and Wolf
(Heald, F. D., and Wolf, F. A. Plant-disease survey in the vi-
cinity of San Antonio, Texas. U. S. Dept. of Agr. B. P. I. Bul.
226:42, 1912) of a disease highly similar to the one in question,
contains no reference to any disease of peppers resembling this
one. In the publication cited appears the following:
"Bactesiauleaf spot [of pepper]. The leaves have small, ele-
vated, brown spots from 0.5 to 1 mm. in diameter. The leaf
tissue between them is more or less chlorotic. Each pustule is
crowded full of bacteria. No record has been found of a pepper
diseas- due to these organisms. . Specimens collected:
Uvalde, 1950."
Fig. 7.-Pepper leaf bacterial spot produced by inoculation with
pure culture of the bacteria; 89 days after inoculation
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Annual Report, 1917
Comparing this description of the trouble with the one given
by the writer it can be readily seen that with the exception of
the color and size of the spots there is no difference between the
two accounts. In Heald and Wolf's description the red hue of
the spots might have been overlooked, or, if the description was
made from old material, the color might actually have disap-
peared. The size of the spot is not an essential character. Be-
sides, the writer's observa-
tions relative to the spots pro- -
duced in the greenhouse show
that they may remain for a .
long time of a more or less
uniformly small size-a size.
such as stated by Heald and -
Wolf. Therefore, the writer
believes the two diseases are -.
probably identical.
PEPPER PINK JOINT
Pepper pink joint is a dis-
ease little if at all known, af-
fecting stems of the pepper
plant. In the cases observed
the disease starts its work in
the juncture of two branches,
hence its name. (This name
was given by the grower who
sent specimens of the disease
to the laboratory.) Diseased -
areas (fig. 8) often have a dis- Fig. 8.-Pepper stems affected with
tinct zonation of color varying pink joint. On the figure to the
Right may be seen a distinctly broad
from pale pinkish-buff to cin- zonation
namon and brown. Branches
and stems affected with the disease soon wither and die.
Two series of isolations of the organism associated with the
disease were made and both resulted in pure growth of a fungus
that could not be distinguished from Sclerotinia libertiana Fuckl.
This fungus is known to cause several important diseases of
other truck crops and probably is the cause of this disease, too.
As yet no inoculations have been made to substantiate the theory.
The trouble so far has been found only in one field, and in
that case the damage amounted to a small percentage of the
number of plants in the field.
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OTHER DISEASES OF IMPORTANCE
TOMATO BACTERIAL BLIGHT (Bacillus solanacearum E. F. Sm.),
observed in many tomato fields last spring and early this summer,
often caused great damage to the crop; the damage sometimes
amounting to loss of an entire crop. Crop rotation, ridding the
soil of root-knot nematodes, field sanitation and control of in-
sects working on tomatoes, have been recommended as measures
against the disease.
TOMATO FUSARIAL WILT (Fusarium lycopersici Sacc.) was not
uncommon and in some instances caused a considerable damage.
Crop rotation and field sanitation have been recommended for
this trouble.
TOMATO EARLY BLIGHT (Macrosporium solani E. & M.) was
a common and more or less destructive disease this season, altho
not as bad as during the preceding season. Spraying with
4-4-50 bordeaux mixture has been recommended for this disease.
POTATO LATE BLIGHT (Phytophthora infestans (Mont.) DeBy.)
was probably the most important among diseases of Irish pota-
toes. First outbreaks of the trouble came to the writer's notice
at the end of March, and specimens of the disease were received
up to the middle of April. Laboratory records show that the
disease appeared at about the same time in 1912. These definite
records are not numerous enough to warrant conclusions. If
observations in later years show also that the disease appears
at about the same time each year the information will be of
importance in seeking to establish the proper time for spraying
Irish potatoes to control late blight. Present indications are
that the first spraying must be made about the middle of March.
This applies of course only to potato fields in which the plants
are some five or more inches high. The usual method of control,
spraying with 4-4-50 bordeaux mixture, has been recommended
for this disease.
How much actual damage was done to the crop by this disease
the writer had no opportunity to determine. In one small field
as much as half the crop was lost. The damage in most cases
did not exceed 20 percent of the crop and in many fields in the
same region (the Hastings district and some other places, mainly
on the East Coast) the disease caused little or no damage. This
might naturally be expected because the season on the whole was
too dry for a general development of the disease.
POTATO BACTERIAL BLIGHT (Bacillus solanacearum E. F. Sm.)
and SCLEROTIAL BLIGHT (Sclerotium rolfsii Sacc.) were not un-
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Annual Report, 1917
common diseases and caused considerable damage in some iso-
lated instances. Control measures for bacterial blight of po-
tatoes are the same as those for the similar blight of tomatoes.
To control sclerotial blight, spraying the ground around the
plant stems with a good fungicide has been recommended.
POTATO EARLY BLIGHT (Macrosporium solani S. & M) was
common this season, but not important.
PEPPER CERCOSPORA SPOT (C. capsici Heald and Wolf) was
quite common and in. several fields, destructive. Production of
young plants in a new or a sterilized soil, sanitary measures,
and spraying with bordeaux mixture, were control measures
recommended for this disease.
CELERY FOOT ROT (Sclerotinia libertiana Fuckl.) was more
destructive this season than for a number of years previous, not
infrequently affecting some 20 percent of the plants. It appears
that the freeze in February which greatly injured celery plants
created conditions specially favorable to the development of the
disease. Field sanitation has been recommended.
CELERY HEART ROT (bacterial?) has been of unusual import-
ance. Judicious fertilization and irrigation, combined with field
sanitation, and control of other celery diseases weakening the
plants, have been recommended as control measures.
CELERY EARLY BLIGHT (Cercospora apii Fr.), often known in
Florida as "rust," while as common as usual did not cause much
damage owing to the general practice of spraying celery plants
with bordeaux mixture.
CELERY LATE BLIGHT (Septoria petroselini Desm. var. apii
Br. & Cav.) was observed in a few fields near Sanford, but was
kept well in check by spraying with bordeaux mixture.
WATERMELON ANTHRACNOSE (Colletotrichum lagenarium
(Pass.) Ell & Halst.) was observed in a few instances to be
causing considerable damage. Spraying with bordeaux mixture
was recommended.
Besides the foregoing diseases, the following were common
altho not very prominent this season: bean anthracnose and
blight, cucumber downy mildew, lettuce drop and black rot, and
damping off of various plants.
PINEAPPLE WILT
Work on pineapple wilt was started the preceding year and
the results were reported in the Experiment Station annual re-
port for 1916, pages 93R-98R. This work led the writer to con-
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Florida Agricultural Experiment Station
elude that the disease is at least greatly assisted if not caused by
activities of the nematodes, Heterodera radicicola (Greef) Mul-
ler, which are responsible for the common rot-knot of vegetables
in Florida. Plantings of pineapple slips this season in green-
house soil infested with nematodes show that pineapple roots
are readily attacked by them, altho it can not yet be shown that
nematodes cause the wilt. Field observations and some isolation
work this year support the findings previously reported but do
not present any new developments.
Examination of plots used in the experiments to determine
the effect of humus in the soil and of slip selection on the control
of wilt shows that neither of the factors has any direct effect.
The disease was observed in all plots, checks included. The plots
well supplied with humus, where old pineapple plants were
turned under, showed a considerably more rank growth than the
plots poor in humus, where the old plants were removed. At
the time of observation, December, 1916, there was no difference
between plots planted with slips selected from healthy plants
and plots planted with slips from plants affected with the wilt;
all plants being of about the same size and equally affected with
the disease. All the plots were in an old pineapple field badly
affected with wilt.
On the assumption that the nematodes are closely connected
with the progress of the disease, cooperative experiments were
undertaken this year to determine the effect of nematode control
on the wilt. It is yet too early to expect any results from these
experiments.
Respectfully,
C. D. SHERBAKOFF,
Associate Plant Pathologist.
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Annual Report, 1917
REPORT OF LABORATORY ASSISTANT IN PLANT
PATHOLOGY
P. H. Rolfs, Director.
SmI: I submit the following report of the Laboratory Assist-
ant in Plant Pathology for the fiscal year ending June 30, 1917.
PECAN DIEBACK
In the annual report for last year it was shown that the my-
celium of the fungus Botryosphaeria berengeriana De Not.,
which is commonly associated with the parts of pecan trees
affected with dieback, produces the general symptoms of that
disease when introduced under more or less aseptic conditions
into wounds of healthy branches of pecan trees.
In order to determine the more natural way in which this
fungus attacks the healthy tree in the field, in addition to the
wound inoculations, previously reported, mycelium from pure
culture and pieces of bark containing the spore stages of the
above named fungus were placed on the surfaces of five branches
in different stages of growth, and covered with moist cotton,
wrapped in paraffined paper, and tied. The surfaces, to which
the inoculum was applied, were washed with 1:1000 solution of
bichloride of mercury, followed with sterilized water. No in-
fection took place.
Having obtained in culture, spores of the foregoing fungus by
the paraffin method previously described, spore inoculations on
five seedling pecan trees in pots were carried out. These trees
were started from seeds early in the spring, and, by the time of
the inoculations, had from three to five leaves on them. The
trees were sprayed with sterilized water and masses of spores
were placed on the moist upper and lower surfaces of the leaves
and on the trunk of the trees. These and three check trees were
placed under bell jars. In the course of four weeks symptoms
of dying from the top were observed in three of the inoculated
trees and in one of the checks. Later all the trees were dying.
Reisolations from two inoculated trees gave a mycelium identical
with Botryosphaeria, while the checks gave various growths.
Apparently the conditions in the greenhouse and under the bell
jars were not favorable for the normal development of the trees.
Therefore, similar experiments were carried out in the field on
young pecan trees which were planted in the winter of 1916 on
the Experiment Station plots. Five succulent shoots were se-
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Florida Agricultural Ezperiment Stuation
elected on five trees, the masses of spores applied to their moist
surfaces and the whole twig wrapped rather loosely with paraffin
paper. All these have passed the season without showing any
symptoms of disease. Further work along this line is being
carried on.
H. S. Fawcett in his preliminary report on his investigations
of Melaxuma of the Walnut "Juglans regia" in California de-
scribes a disease which (Melaxuma of the Walnut "Juglans
regia." Bull. 261, Cal. Exp. Sta. 1915) suggests similarities
to pecan dieback, except that there is rarely any oozing of
"black sap" from the cankers in diseased pecan wood. A tube
culture of Dothiorella gregaria Sacc. was obtained thru Fawcett
from California in order to make a comparative study of the
Dothiorella from California and the Botryosphaeria from Flor-
ida. The following results bear upon the relationship of the two:
1. On cornmeal agar and tubed bean pods the growth charac-
ters, color, and copiousness of mycelium in the two fungi do not
differ to any distinguishable degree. No spores were observed
on these media in either of two fungi.
2. On paraffined hickory and pecan plugs mature pycnidia
were produced in both fungi. The perithecia and spores of both
fungi as found in culture agree sufficiently with the description
given by Fawcett for Dothiorella gregaria Sacc. (p. 140). Illus-
tratiqns of perfect and imperfect spore forms of Botryosphaeria
were given in the previous report.
3. Mycelium from pure culture of both fungi were used in
the spring and summer of 1916 for inoculation in pecan trees
on the Experiment Station grounds. From the results obtained
in this series it would seem that the two fungi do not differ in
their ability to infect pecan. The California Dothiorella pro-
duced similar, and in some cases larger, dead areas around the
points of inoculation in the bark and wood of pecan trees as
Botryosphacria. A perfect stage which was identical with that
produced by Botryosphaeria was later in the summer found in
the lesions which were caused thru the introduction of either
of the two fungi. These inoculations were carried out in the
field as far as possible under more or less aseptic conditions, i. e.,
the surfaces of the parts intended for inoculation were washed
with 1:1000 bichloride of mercury solution, rinsed with sterilized
water, wounds cut with sterile scalpel, mycelium inserted in
wound and wrapped with paraffined paper.
The wounds were kept Wrapped for a month or more after the
Annual Report, 1917
first apparent breaking out of stromatic bodies thru the epi-
dermis of the bark adjacent to the cut.
TABLE 26.-INocLATONs wrrITH BOTYOSPHAERIA FROM PECAN AND DoTH-
IORELLA FROM WALNUT (California)
Tree | No. of inoculations I Results
| Botryosphaeria Dothiorlla I
1. 6 ft. high 1 near top of tree 1 Areas killed 3 inches long
perfect stage in both.
2 in. diam. 1 in trunk 1 Areas killed, 2-4 inches
perfect stage in both.
1 check 1 check Healed.
1 twig 1 Slight injury.
2. 6 ft. high 1 lower part of
1 in. diam. trunk 1 Areas killed 2 inches.
1 check 1 Healed.
3 in large limb 3 2 Dothiorella infections,
3. 15 ft. high 1 Botryosphaeria.
4 in. diam. 1 in crutch 1 2x4 areas killed; perfect
and imperfect stages in
both fungi.
3 near bases of
young branches 3 All infected, small areas.
2 central limb 2 Large infected areas.
4 checks 4 Healed.
A 100-acre section of a pecan grove at Lomoko was gone over
in the spring of 1916 and all the visible deadwood was cut out.
a few trees in this section were showing symptoms of Rosette,
and 35 percent of the trees had dieback. In the fall of the-ame
year, and in the spring of 1917 an appreciable reduction in the
occurrence of new outbreaks of dieback in this section was
evident.
AN UNDESCRIBED GNOMONIA ON PECAN LEAVES
In the fall of 1916 some green pecan leaves from a grove in
central Florida were brought to this laboratory for examination
as to the presence of the Scab fungus, Fusicladium efusum. Later,
a second liberal amount of similar leaves were received. The
leaves were of normal size and mature. Some Fusicladium was
present on the leaves but the most prominent feature of the
diseased leaves was a brown spot fairly abundant, and free, ap-
parently, from any hyphomycete. (Fig. 9.) Upon a closer
examination of these spots, especially the older and larger ones,
straight (some slightly curved) black beaks are visible, breaking
thru the epidermis of the lower surface of the leaf. These beaks
are usually grouped toward the center and are rather sparsely
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scattered. (Fig. 10.) These are the elongated ostioles of more
or less spherical perithecia which are embedded in the leaf tissue
and which contain numerous asci with two, rarely three, unisep-
tate, hyaline, but sometimes slightly colored spores. (Fig. 11.)
The membranous
character of the
perithecium, the
dark color of the
walls, shape and
ringed spores of
the asci, morphol-
ogy of the spores
and the elongated
beak, place this
fungus at once
into the genus
Gnomonia. How-
ever, Saccardo
and Engler
Prante make no
mention of a Gno-
monia possessing
less than 4 spores
to an ascus.
SWolf described
an 8-spore Gno-
monia on the
hickory.
DESCRIPTION OF
THE SPOT
The spots vary
from very irregu-
.- -- lar, smooth, mar-
Fig. 9.-Gnomonia spot on pecan leaves. Natural size ginal indefinite,
dark, nearly black
specks to more or less regular, large, sometimes running together
in blotches, not circular, marginate, brown to blackish-brown,
and sometimes gray due to the shrinking of the parenchyma
from the epidermis. The fungus could not be found in, nor
obtained in culture from, the tissue of young spots. Mature
perithecia were found only in large spots about 1 c.m. in diam-
eter. The perithecia are completely embedded in the tissue, the
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Annual Report, 1917
beaks only breaking thru and protruding above the level of the
epidermal layer.
This fungus was grown in culture from single asci which were
obtained in the following way: With a sharp needle a perithe-
Fig. 10.-Gnomonia on pecan leaf, showing small beaks break-
ing thru epidermis. Enlarged
cium was lifted from the leaf tissue, crushed in a sterilized drop
of water in a sterilized petri dish, and agar poured over it. The
two-spored asci could easily be located with a low power lens in
the agar. Thus single asci were transferred to other agar plates
and germination could be watched from time to time. A large
Fig. 11.-Perithecium of Gnomonia n. sp. Greatly enlarged
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number of the spores in several trials
did not germinate. The spores send
out two germ tubes from each end,
and branching takes place in about
4 to days. In cornmeal agar the
white colonies make a slow and com-
pact growth. (Fig. 12.) When the
Ssmyceliunm is transferred to sterilized
an d nearly mat u re cowpea pods (figs.
1:, 14) the growth is at first slow
and compact: in 5 to 8 weeks the
mycelium apparently collapses and
almost disappears and perithecia are
produced. On
mature steril-
ized hickory
leaves the my- .
celial growth is
scant but peri-
thecia are pro-
F:g. 12. -Gnonionia colonies in
cornmeal agar; 2 weeks old dulced inl great-
p;reatly enlarged ei a eiu I dan ce
in about two
months from transfer. ( Fig. 15.) This fiun-
gus was grlo\\l inl piure culture oil cornmeal
agar slants. bean agar slant. standard agar
slant, and hickory leaves. yollng pecan leaves
and succulent bean pods. Standard nutrient
agar seems to be the poorest media for this Fig. 13.--Gnomonia
culture on cowpea
organism. pod; 2 weeks old
In order to ascertain the constancll of the
disporous character of this fungus, single asci from the peri-
thecia which were produced oil sterilized hickory leaves and
cowpea pods from the first dilation, were again planted in
cornmeal agar and transferred to the above two media. The
perithecia in this series, the second generation, were .similar in
Fig. 1 I.- (;nmonioia culture on .'owpea pod; 2 months old
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Annual Report, 1917
all respects to those of the first and to those in the original leaves.
A third generation was grown and no change was observed.
INOCULATIONS
Spores of this fungus were placed on moist leaves of young
hickory trees. One tree was sprayed with a suspension of
Fig. 15.-Leaves inoculated with Gnomonia spores; hickory on
right; pecan on left
spores. On another a single perithecium was placed and crushed
on each of ten leaves, and a third received perithecia previously
crushed in sterile water. These trees were left under bell
jars. Two trees were placed under jars but not inoculated.
After four weeks numerous spots, resembling those on pecan
were observed on all inoculated leaves. The tree which was
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sprayed with a suspension of spores showed only scant infection.
Check trees did not show any infection. A similar experiment
was carried out in the greenhouse on young seedling pecan trees.
On these the spots produced were much larger than on the
hickory.
Reisolations of the inoculated hickory leaves gave a mycelium
in most cases, similar to the one obtained from the single asci
referred to above. The reisolations from the pecan were all over-
run by a fungus which is apparently different from Gnomonia.
Respectfully,
JULIUS MATZ,
Laboratory Assistant.
Annual Report, 1917
REPORT OF CHEMIST
P. H. Rolfs, Director.
SIR: I submit the following report of the Chemist for the
fiscal year ending June 30, 1917.
CITRUS EXPERIMENTAL GROVE
Treatment.-The grove was fertilized three times per year
as usual, each tree receiving four pounds of fertilizer instead of
two. Cultivation was continued as usual and velvet beans seeded
in the middle to supply leguminous cover crop, cowpeas having
been found to mildew badly on this particular plot of land.
Those plots receiving alkaline materials, viz., 21, 11, 30, 28,
and 39, continue to show the effects of such treatment. They
are still badly frenched and present a very unthrifty appearance.
There was very little fruit on any of the plots.
Effect of Freeze.-The grove was rather severely injured by
the cold weather occurring in February, 1917, and which was
prevalent over a large portion of the State.
The grove was visited on March 8 to observe the effect of the
freezing weather upon the trees. The amount of defoliation was
noted as well as the distance to which the twigs were killed
back, the character and the amount of new growth coming out
and the amount of new bloom.
During the night of the freeze the wind was from the north
and the greatest damage was noted upon the north side of the
trees. An effort was made to note the effects, if any, of the
various fertilizer treatments in making the trees more or less
resistant to cold. No conclusive data could be obtained with
the exception that it was evident that those plots which were in
a weakened and unthrifty condition when the cold struck them,
suffered much more than the thrifty trees. This unhealthy con-
dition was due largely to the fertilizer treatment received. Plots
4, 5, 7, 21, 27, 28, 39, and 43 were the hardest hit by the cold.
The first three plots received excessive amounts of fertilizer,
especially nitrogen; plots 21 and 39 have been injured by the
use of ground limestone; plots 27 and 28 by the use of basic slag,
and plot 43 has received no fertilizer since the experiment began,
which would account for its unhealthy condition.
In the plots mentioned the trees were nearly defoliated, it
being estimated that 80 percent or more of the leaves dropped.
In some cases the weaker trees were killed outright; in others
large branches were killed back to the trunk. Where the trees
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Florida Agricultural Experiment Station
were not killed the new growth developing at the time of the
visit was scanty in amount and very weak and unthrifty. In
plot 17, a number of trees were affected with dieback and these
were more susceptible to cold than the others in the same plot.
Those plots which have made the best growth in previous years
were least injured by the cold. In many cases these trees re-
tained at least 60 to 75 percent of their leaves, and the twigs
were frozen back only a few inches.
In conclusion it may be said that the data gathered at this
time goes to show that trees in good healthy condition, receiving
proper care are in much better condition to withstand a freeze
than are those which have been weakened by improper treatment
or neglect.
When the grove was seen in June, the trees had almost entirely
recovered from the effects of the cold, with a few exceptions.
Plot 28 receiving a double amount of basic slag was in very poor
condition still, while the other plots mentioned as being severely
injured were making a very poor growth. Quite a heavy June
bloom was noted on many of the trees.
Measurements of Trees.-In Table 27 are given the measure-
ments of the trees of the various plots taken in June, 1917. Not-
withstanding the severe freeze the trees have made considerable
growth the past year.
The no-fertilizer plot, number 43, has dropped still lower in
the list, now ranking number 39, while in 1916 it ranked 34.
As will be noted in the table, the plots making the least growth
are those receiving excessive amounts of fertilizer.
TABLE 27-AvERAGE GAINS IN DIAMETER OF TREES FROM JUNE, 1909, TO
JUNE, 1917
Gain in
Plot 32nds o
an inch
2 117
1 116
47 113
48 113
12 112
13 111
25 105
35 103
46 103
8 102
31 102
37 102
9 101
36 101
Fertilizer Treatment
Standard.
One half Standard.
Nitrogen from dried blood. Clean culture.
Nitrogen from nitrate of soda. Clean culture.
Standard air-slaked lime.
Standard, mulched.
Phosphoric acid from steamed bone.
Phosphoric acid from floats (four times the amount).
Standard.
Phosphoric acid and potash decreased by one half.
Standard.
Potash from low-grade sulphate.
Phosphoric acid and nitrogen decreased by one half.
Phosphoric acid from floats (4 times amount).
Cottonseed meal.
96R
f
97R
Annual Report, 1917
TABLE 27. (Continued)
I Gain in
Plot 32nds of
an inch
11 99
6 99
22 99
30 99
44 98
45 97
16 97
20 96
24 94
23 94
32 94
29 93
26 92
21 92
38 91
42 91
3 90
19 89
15 87
10 87
14 86
34 86
27 85
33 85
43 85
18 83
7 82
40 81
41 81
28 80
17 72
39 68
5 60
4 49
Fertilizer Treatment
Standard, ground limestone.
Phosphoric acid and potash increased by one half.
Half nitrogen from cottonseed meal, half sulphate ammonia.
'Acid phosphate, nitrate soda, hardwood ashes.
Standard.
Standard, mulched.
Half nitrogen, nitrate of soda, half from sulphate of ammonia.
Nitrogen from cottonseed meal.
Phosphoric acid from dissolved bone black.
Half nitrogen, cottonseed meal, half nitrate of soda.
Phosphoric acid from dissolved bone black.
7% percent potash in June and October, 3 in February.
Phosphoric acid from steamed bone (twice amount).
Nitrogen from cottonseed meal. Ground limestone.
Potash from muriate.
Potash from nitrate of potash; balance of nitrogen nitrate
of soda.
[Twice standard.
Half nitrogen from nitrate of soda, half from dried blood.
'Nitrogen from nitrate of soda.
Nitrogen and potash decreased one half.
Standard.
Phosphoric acid from floats (twice the amount).
Phosphoric acid from Thomas slag, nitrate of soda.
SPhosphoric acid from floats.
!No fertilizer.
Half nitrogen from sulphate of ammonia, half dried blood.
'Nitrogen and potash increased by one half.
IPotash from kainit.
IStandard.
Phosphoric acid from Thomas slag (twice amount), nitrate
of soda.
Nitrogen from dried blood.
Standard, ground limestone.
lPhosphoric acid and nitrogen increased one half.
Four times standard.
PHOSPHORIC ACID IN GROVE SOILS
In 1914 and 1915 samples of soils were taken from all the
plots of the experimental grove, both from near the trees where
the fertilizers were applied and in the middle of the rows where
no fertilizer has ever been used. These samples consisted of
three sets taken in March and December of 1914 and in July,
1915, and as time permitted, were analyzed for phosphoric acid.
Both total and acid soluble phosphoric acid were determined.
The latter determination was made by treating the soil with
weak nitric acid (fifth normal) and determining the amount of
phosphoric acid which went into solution. This method has been
used by a number of soil chemists to determine the so-called
"available" phosphoric acid of the soil.
The results obtained in this work are given in tables 28 and 29,
r!
Florida Agricultural Experiment Station
the figures in the three columns under the word "check" being
analyses of the samples of soil taken from the middle of the rows
of trees and consequently represent samples which have never re-
ceived any fertilizer. In order to note the increase in phosphoric
acid content in the soil due to additions of this material in the
fertilizer, the check figures should be compared with the plot
figures for the same months. Such a comparison brings out the
fact that in general there has been a considerable increase in the
phosphoric acid content of the plot soils. This increase is great-
est in plot 4 where there is an average increase of over 52
percent. Plot 36 shows the next largest increase, 43 percent.
These two plots have received four times as much phosphoric
acid in the fertilizer as the standard plots. Plots 16, 42 and 44
received only the standard amount, yet show an increase of over
20 percent.
TABLE 28.-PHOSPHORIC ACID IN SOILS or EXPERIMENTAL GROVE
No.
1 ........ .
S|
3 _
6 .......
7 .......
8 ........
9 .. ...
10
10 ........
11 ..
12 .....
13 ......... .... ...
14 ....... ......
15 .. ... ..........
16 ...... .... .......
17 ... ..... ......
18 .. ................
19
20... .....
2 1 ... ........... ...
22 .............
23
2 4 ..........
25 . ........
26 .. ..........
2 7 ............... .. i
28
2 8 . .......... ..
2 9 .................
30 ....... ..
3 1 ......................
3 2 .................. .
3 3 ......................
Plot
March Dec.
.090 .101
.119 .119
.150 .147
.167 .145
.121 .112
.125 .147
.102 .129
.102 .101
.102 .100
.108 .100
.113 .129
.108 .109
.116 .135
.106 .124
.110 .109
.137 I .145
.140 .140
.124 .122
.115 .116
.115 .105
.114 .113
.115 .118
.145 .141
.134 .135
.116 .122
.143 .161
.114 I .127
.134 .126
.119 .123
.111 .109
.135 .144
114- .124
.101 .107
July
.09A
.121
.155
.162
.137
.135
.119
.105
.117
.113
.136
.118
.140
.135
.120
.153
.148
.140
.128
.127
.118
.119
.134
.142
.122
.147
.123
.130
.114
.124
.134
.115
.111
March
.091
.102
.120
.102
.102
.120
.102
.091
.114
.097
.111
.108
.108
.111
.097
.114
.128
.120
.102
.102
.102
.102
.120
.128
.108
.127
.106
.104
.104
.106
.127
.108
.099
Check
Dec.
.085
.098
.115
.103
.103
.115
.098
.085
.115
.095
.110
.107
.107
.110
.095
.115
.127
.121
.105
.099
.099
.105
.121
.127
.094
.117
.098
.116
.116
.098
.116
.094
.097
July
.087
.099
.109
.098
.098
.109
.099
.087
.118
.097
.114
.102
.102
.114
.097
.117
.124
.114
.088
.082
.082
.088
.114
.124
.107
.121
.099
.108
.103
.100
.121
.107
i.094
98R
Annual Report, 1917
TABLE 28. (Continued)
Plot Check
No.
March Dec. July March Dec. July
34 .131 .137 .141 .107 .105 .107
35 ... .122 .135 .151 .104 .100 .098
36 ..... .126 .138 .182 .088 .096 .096
37 .109 .110 .108 .088 .096 .096
38 .. .129 .131 .127 .104 .101 .098
39 .105 .121 .125 .107 .105 .107
40 .113 .122 .117 .099 .097 .094
41 .124 .109 .110 .101 .099 .101
42 .112 .119 .120 .092 .094 .095
43 .119 .113 .102 .111 .109 .114
44 .125 .125 .30 .105 .103 .106
45 .. ... .117 .132 .124 .105 .103 .106
46 .. .129 .117 .125 .111 .109 .114
47 113 .100 .106 .092 .094 .099
48 .. ... .126 .110 .117 .101 .098 .101
The work reported in table 28 shows that soils of a type simi-
lar to that on which the grove is situated have the power to hold
large quantities of phosphoric acid applied in fertilizers, and
is in line with the work with soil tanks now being carried on
by this department. Much of this phosphoric acid is fixed near
the surface of the soil as the samples were taken to a depth of
only nine inches.
The results for acid soluble phosphoric acid given in table 29
are rather inconclusive, but several interesting facts are brought
out. Plot 4 receiving acid phosphate contains, when calculated
to the acre basis, 600 pounds more of phosphoric acid than plot
36, receiving a like amount in the form of floats.
Plot 3 receiving acid phosphate contains more "available"
phosphoric acid than plots 34 and 26 which receive the same
amount in the form of floats and steamed bone.
Owing to the influence of other factors, the tree growth and
"available" phosphoric acid content of these plots are impossible
of correlation.
99R
100R
Florida Agricultural Experiment Station
TABLE 29.-ACID-SOLUBL PHOSPHORIC ACID IN GIOV
SPlot Check
No.
i March Dec. July March Dec. July
1 ... ...... .026 .030 .029 .022 .023 .020
2 ... .037 .038 .037 .022 .023 .019
3 ................ .063 .048 .064 .029 .032 .029
4 .....-......... .095 .070 .091 .029 .032 .029
5 --- ---- .056 .044 .065 .029 .032 .029
6 ... .046 .059 .046 .029 I .026 .024
7 ....- .032 .036 I .041 .022 .023 .019
8 ... ..... .032 .031 .032 .022 .023 .020
9 ........ 031 .023 .028 .023 .024 .026
10 ...... 028 .025 .037 .020 .020 .019
11 .... .035 .034 .044 .026 .026 .022
12 ........ .043 .035 .042 .028 .026 .028
13 ... .......... .047 .044 .054 .028 .026 .028
14 ... ........... .035 .038 .045 .026 .026 .022
15 ....... .045 .032 .035 .020 .020 .019
16 .............. .042 .043 .048 .023 .024 .026
17 ............... .036 .032 .038 .027 .024 .026
18 ............... .028 .031 .041 .024 .025 .023
19 ................... .037 .034 .039 .021 .023 .021
20 .............. 031 .031 .039 .023 .026 .021
21 .. .035 .038 .038 .023 1 .026 .021
22 .. ............ 037 .033 .038 .021 .023 .021
23 ...... ........ .042 .030 i .037 .024 .025 .023
24 ....... .038 .038 .044 I .027 .024 .026
25 ..030 .029 .037 .025 .026 .022
26 .044 .041 .045 .026 .029 .024
27 .031 .034 .034 .022 .021 1 .022
28 .. 046 .038 .047 .020 .023 .025
29 .032 .037 | .033 .020 .023 .025
30 ....... .033 .031 .041 .022 .021 .022
31 .......... .043 .037 .043 .026 .029 .024
32 ... .. 040 .041 .037 .025 .026 .022
33 036 .031 .039 .024 .025 .024
34 ........ .047 .037 .052 .023 .026 .022
35 ...... .046 .051 .067 .021 .023 .019
36 ............... .051 .052 .092 .017 .020 .018
37 .................. .035 .033 .029 .017 .020 .018
38 ..................... .042 I .036 .039 .021 .023 .019
39 ................... .033 .041 .039 .023 .026 .022
40 .................. .041 1 .043 .040 .024 .025 .024
41 ......... ...... .038 .029 .033 .023 .024 .023
42 .................... .033 .036 .040 .019 .020 .018
43 ................ .026 .021 .020 .024 .025 .021
44 ............... .042 .039 .045 .029 .030 .029
45 .. .041 .050 .046 I .029 .030 .029
46 ............ .037 .030 .036 .024 .026 .021
47 ......... 036 .030 .031 .019 .020 .018
48 ........... ..' .043 .036 .037 .023 .024 .023
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