|
University of Florida
Agricultural Experiment Station
REPORT FOR THE FISCAL
YEAR ENDING JUNE 30, 1912
University of Florida
Agricultural
Experiment
Station
Report for the Fiscal Year
Ending June 30
1912
Gainesville. Florida
Pepper Publishboi & Printing Co.
March. 1913
CONTENTS
PAam
LETTER OF TRANSMITTAL TO GOVERNOR OF FLORImDA.......----------....... vii
BOARD OP CONTROL --------------.. ... ...----------------------------- vl
EXPERIMENT STATION STAFF ----------------.------------------ viii
LETTER OF TRANSMITTAL TO CHAIRMAN OF BOARD OF CONTROL-------- ix
Conditions of Work---------------------------------------- ix
Development of the Grounds------------------------------- x
Lines of Work ------------------------------------------ xii
Bulletins -------------------------------------------- xvifl
REPORT OF AUDIT--------------------------------------------- XX
REPORT OF ANIMAL INDUSTRIALIST--------------------------------- xt
Dairy Herd ------------------------------------------------ xxi
Beef Herd ---------------...------------------------------- xxv
Steer-Feeding Experiment ------------------------------- xxv
Cattle Breeding ------------------------------------------ xxv
Hogs ------------------------------------------------- xxix
Pig-Feeding Experiments --------------------------------- xxix
Yokohama Beans ---------------------------------------- xx
Japanese Cane -----------------------------------------xxii
Natal Grass --------------------------------------------...... xxxv
Guinea Grass ----------------------------------------- xxxv
Para Grass --------------------------------------------- xxxv
Kudzu -------------------------------.--------.--.---- xxx
Fertilizing Grasses ------------------------------------ xxxvi
Cotton ---------------------------------------------.... xxxvi
REPORT OF ASSOCIATE CHEMIST---------------------------- xxxviii
Citrus Experimental Grove------------------ -...xxxviii
Soil Tank Investigations --------------------------------- xiii
REPORT OF ENTOMOLOGIST------------------------------------ viii
"Natural Mortality" of the Whitefly------------------------xlviii
Spread and Parasitization of Aleurodes howardii -- ....------------ v
Whitefly and Fungi in Citrus Groves----- --------- lvi
Importation of Parasites .....---------...--- Ix
Thermal Deathpoint and Optimum Temperature of Aleurodes
citri --------- --- ------------------ Ix
Spraying Tomatoes for Thrips ----------------- x----- d
Insects of the Year ..---------------------------------------. xii
REPOr oF FouRMu PLANT PATHOLOGIST------------------- ------ iv
Stem-End Rot ----------------------------- Ixiv
Effects of Spraying--------------------------------- .....xxii
Gumming -------------------------------- ------------ Ixxviii
REPORT OF PLANT PATHOLOGIST------------------------------ ci
Lines of Work----------------------------------------- xiii
Melanose -------------------------------------------- xeiii
Citrus Scab ..............-------------------------------------------...... xcvi /
Potato Disease ------------------------------------------ xcvii
Vegetable Diseases -------------------------------------........ xcviii
REPORT OF ASSISTANT PLANT PATHOLOGIST------------------- xcviii
Bacterial Lettuce Disease--------------------------------- xcviii
A New Cucumber Disease------------------------------
REPORT OF PLANT PHYSIOLOGIST---------------------------- cii
Experiments with Citrus Dieback ----------------------------..ci........e
Gumpockets Produced by Dieback in Citrus Wood ------------ v
REPORT OP ASSISTANT BOTANIST---------------- ------ cXV
Third Generation of the Cross Between Velvet and Lyon Beans- cxv
Corn Crosses ------------------------------------------ cxxvii
Mailing and Editorial--------------------------------- cxxix
iv Contents
BuLLumr 107-STEM-END ROT O OrCITUS Faurrs. PAGES 1-28.
Introduction ------------------------- 3
Injury from the Fungus 5------------------------ 6
How the Fungus Lives and Grows--.......------------------------5
Description of Stem-End Rot .........--...........................--------------------------- 6
Conditions Favoring Stem-End Rot---------------------------- 7
Infection Experiments .......................---------------------- 8
Inoculation of Green Fruit and Branches on the Tree............------ 12
Description of the Fungus---.....-------------------------------13
Experiments for Control-- ----------- -------------------. 16
Disinfection of Fruit....---------------------------...-------...... 19
Control Measures ---------------------------- 19
Catalogue of Rots, etc----------- -------------- ------------ 22
BuLLaTlN 108-DISEASES OF CITRUS FRUITS. PAGES 25-47.
Introduction --------------------------- ----------------- 27
Diseases Affecting the Epidermis-
Rust Mite Russeting--------- ...............-------------------------- 27
Melanose ------------------------------------------- 29
Russeting and Tear Streaking Caused by Withertip Fungus -.....----. 30
Buckskinning ---------------- ---------------------- 32
Silver Scurf and Thrips Marks............---------.......---------------- 32
Sun Scald ---------------- -- ------------------------33
Diseases Affecting the Peel-
Dieback (Ammoniated) Markings.... -------------------------34
Anthracnose ----------------------------------------- 86
Chemical Injury ------------------------------------- 38
Nail-Head Rust -------------------------------------- 40
Scab ----------------------------------------------- 41
Splits --- ----------------------------------------------42
Creasing- ----- ---------------------------------- 42
Knots in Rind -------------------------------------- 43
Mechanical Injuries -----------------------------------43
Diseases Affecting the Interior of the Fruit-
Blue Mold Rots...........--------------------------------------44
Stem-End Rot --------------------------------------- 45
Diplodia Rot ----------------------------------------- 46
Black Rot ---------------------------------------- 47
BULLETIN 109.-CrITus SCAB. PAGE 49-60.
Introduction -------------------------------------------- 51
History of Scab ------------------------------------------ 53
The Fungus in Cultures..----.. ---------------------------- 54
Germination of Spores-------- --------------------------- 56
Infection Experiments ------------------------------------- 57
Experiments for Control ------------ ---------------------- 58
Preventive Measures .................------------......--------------------- -----59
References -------------------------------------------- 60
BULLETIN 110.-NATIVE AND GRAD CATTLE-BREEDING. PAcES 61-72.
Introduction -----------------------63
Beef Breeds of Cattle--......-- ---------------- 64
Comarative Experiment with Grade Steers--- ------------------ 64
Small Size Largely Due to Insufficient Feeding ------------------ 69
Young Beef Most Profitable ..--------..---------------------- 70
Contents
PRESS BULLETINS
172.-Bulletins and Reports on
Hand.
173.-Cultivation of Sweet Pota-
toes.
Tools to Use.
Disk Cultivator Better Than
Plow.
174.-Choosing and Breeding Pigs.
How Prolificness May Be
Maintained.
175.-Curing the Hay Crop.
Hay Making.
Stage in Which to Cut.
Crab Grass.
Mexican Clover.
Beggarweed.
Cowpeas.
Hay-Cock Covers.
176.-Bedding Seed-Cane.
The Time to Save Seed-Cane.
Location of Bed.
Selection of Seed-Cane.
Methods of Laying Down the
Seed-Cane.
Covering the Bed.
177.-Storing the Sweet Potato Crop.
Digging Sweet Potatoes.
Storing Sweet Potatoes.
178.-Velvet Bean Seed.
Short Crop, High Prices.
Save Seed.
Cost of Growing.
179.-Pig-Feeding Experiments.
Experiment No. 1.
Experiment No. 2.
Experiment No. 3.
Experiment No. 4.
180.-Pruning for Withertip and
Stem-End Rot of Citrus.
How to Prune.
When to Prune.
Cutting Out Useless Trees.
181.-Bulletins and Reports on
Hand.
182.-Balanced Rations for Dairy
Cows.
Rations of Home-Grown
Feeds.
Rations of Purchased Feeds,
183.-Spraying and the Citrus Pur-
ple Scale.
A Spraying Experiment.
Scale-Insects in September.
Scale-Insects in November.
Bordeaux, Lime-Sulphur, and
Others' Formula IV.
Bordeaux Mixture and Scale-
Insects.
184.-Drying Citrus Fruits by
Heated Air.
185.-Growing Sweet Potato Draws.
Location of the Bed.
Making the Bed.
Quality of Seed.
Care of the Bed.
186.-Corn Planting.
Thorough Preparation Before
Planting.
Distance for Planting.
Shallow Cultivation.
Plant Cowpeas or Beggar-
weed.
Seed Plot
187.-Young Beef the Most Profit-
able.
Birth-Weight.
Weight at Weaning.
Profit from Young Beef.
188.-Corn Cultivation.
Depth of Cultivation.
Root Pruning Detrimental.
Implements to Use.
Frequent Cultivation Neces-
sary.
189.-The Small Canning Factory.
Canning Outfits.
Home Canners.
Expense and Returns.
190.-The Control of Thrips on To-
matoes.
The Insect.
Damage.
Treatment.
191.-Native Cattle Small from Lack
of Feed.
INDEX To REPoRT, BULLETINS, AND PRnESS BULLEImNS.
Fig. I.-Experiment Station Hall
Hon. Park Trammell,
Governor of Florida,
Tallahassee, Fla.
SiR: I have the honor to transmit herewith the annual
report of the Director of the Florida Experiment Station, for
the fiscal year ending June 30, 1912.
Respectfully,
P. K. YoNGn,
Chairman of the Board of Control
BOARD OF CONTROL
P. K. YoNG, Chairman, Pensacola, Fla.
T. B. KING, Arcadia, Fla.
E. L. WARTMANN, Citra, Fla.
F. P. FLEMING, Jr., Jacksonville, Fla.
W. D. FINLAYSON, Old Town, Fla.
STATION STAFF
P. H. ROLFS, M.S., Director
J. M. SCOTT, B.S., Animal Industrialist and Assistant Director
B. F. FLOYD, A.M., Plant Physiologist
J. R. WATSON, A.M., Entomologist
H. E. STEVENS, M.S., Plant Pathologist
S. E. COLLISON, M.S., Chemist
JOHN BELLING, B.Sc., Assistant Botanist, and Editor
0. F. BURGER, M.S., Assistant Plant Pathologist
SETH S. WALKER, M.S., Assistant Chemist
JOHN SCHNABEL, Assistant Horticulturist
U. C. LOFTrIN, B.S., Laboratory Assistant in Entomology
F. M. O'BYRNE, A.B., Laboratory Assistant in Plant Physiology
JESSIE URNER, Secretary
K. H. GRAHAM, Auditor and Bookkeeper
M. CREWS, Farm Foreman
Report for Fiscal Year Ending
June 30, 1912
Hon. P. K. Yonge,
Chairman, Board of Control
SIR: 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, 1912, and I respectfully request
that you transmit the same, in accordance with the law, to the
Governor of the State of Florida.
Respectfully,
P. H. ROLFS,
Director
CONDITIONS OF WORK
The good results of the separation of investigational from
instructional work have been well shown this year. The amount
of work accomplished by members of the staff has exceeded that
of any previous twelve months. The time of the investigators
is devoted to research work, being confined to their particular
problems, and nothing is allowed to stand in the way of their
major projects. In such a rapidly developing State as Florida
independent research is especially important. Florida, though
a peninsula, has in many respects insular conditions. We are
therefore thrown upon our own resources to develop an agricul-
ture which is distinctly different from that occurring elsewhere;
and our agricultural problems need especially careful investiga-
tion from the very first. While many of the basic truths of the
agriculture of the more northern sections doubtless apply to Flor-
ida, it is by no means certain that all do. A careful survey of
the agricultural field shows that we have many problems that
are distinctly sub-tropical, to which there is little likelihood that
more northern methods can be adapted.
The Experiment Station Hall (Fig. I), which was designed
and built especially for research work, has proved itself to be
all that could be expected of it. It has conserved a large por-
tion of the time that was formerly lost in the crowded labora-
tories of Thomas Hall, thus giving our men for research work
Florida Agricultural Experiment Station
that amount of time which was formerly used in preparing for
the work or in adjusting themselves to the crowded conditions.
We have had many expressions of appreciation of our work,
but none that are more gratifying than that of individuals who
volunteer private assistance to further the projects undertaken.
Mr. E. 0. Painter, of Jacksonville, has given us $300 to be ap-
plied to the extension of our appliances in the study of fertil-
izers leaching.from the soil. This problem has attracted earnest
attention from those who are giving Florida soils careful study
in the field. Gratifying as it is to have the work of the Experi-
ment Station appreciated in this way, it seems unfair that cer-
tain citizens only should contribute personal aid to secure the
discovery of facts that will be of value to all the people of the
State.
DEVELOPMENT OF THE GROUNDS
The roadway on the Horticultural Grounds that is subject to
heavy traffic has been surfaced with clay. This has been found
to be economical and to make an excellent road. During dry
weather, when this road is likely to become somewhat worn by
traffic, the King drag is used to keep the surface smooth. Imme-
diately after rains, when the clay is still somewhat sticky, the
drag is again used on the surface; this causes the puddling of
the sand and clay and gives the road a hard surface. During the
entire time that the road has been in service (nearly two years
now) the cost of maintenance of the road has been less than
the former expense of keeping it free from weeds. In addition
to this the road makes a more presentable showing than would
be the case with a sand road. (See Fig. II.)
The roadways that are not subjected to heavy traffic have
been graded up and planted with St. Augustine grass (Stenota
phrum secundatum). This has been found extremely satisfac-
tory and makes a good appearance. (See Fig. III.) In the
earlier stages of the growth of this grass the roads had to be pro-
tected from traffic to keep from cutting through the grass and
making ruts and bare spots in it. Since the grass has become
thoroughly matted the roads are used freely by wagons hauling
light loads and also by automobiles. The packing of the sand
by traffic appears to improve the roadways rather than to be
detrimental to them. The soil upon which these roads have been
built is of the light, sandy hammock class. By using the horse
lawn-mower freely, the cost of maintenance of the roads is less
Fig. II.-Clay Road in Horticultural Grounds.
Florida Agricultural Experiment Station
than would be the cost with sand roads. Care and judgment,
however, are necessary to keep these in a presentable form.
LINES OF WORK
During this fiscal year the principal lines of work as laid down
in former years have been continued, and somewhat broadened.
The scope of some of the projects has been somewhat narrowed
to meet the capacity for carrying on the work. As a whole we
have found that better results are obtained by directing our en-
ergies to certain definite problems than by attempting to carry
forward a large number of them simultaneously. One project,
that of breeding native and grade cattle, has been completed so
far as its present aim is concerned. The projects under consid-
eration group themselves naturally, as in former years, into the
following divisions: (1) Horticulture, (2) Animal Industry,
(8) Agronomy, (4) Chemistry, (5) Entomology, (6) Plant
Pathology, (7) Plant Physiology, (8) Co-operative Work.
HORTICULTURE.-This work is being carried on under the
instructions of the Director, and the details are carried out
by the Assistant Horticulturist. The principal lines which were
begun in former years arer being carried forward.
Vegetables.-A considerable number of varieties of tomatoes
have been grown this year to determine their adaptability and
resistance with regard to certain untoward conditions occurring
in Florida fields. This work will be continued for a number
of years, and in the end the average should give us some definite
information as to the value of different varieties. Peppers, egg-
plants, and sweet corn, have also been tested with similar ends
in view.
Udo (Aralia cordata).-One hundred plants were received
from the Bureau of Plant Industry in June, 1910. They were
kept in the greenhouse until conditions for planting in the
nursery were favorable. The plants were set out in rows 4 feet
apart, at a distance of 2 feet in the row. The early growth was
excellent.
The plants produce a vegetable that might be likened to
asparagus. It is quite as palatable as the latter. The flavor
is pleasant and decidedly different from asparagus. For sub-
tropical regions, where asparagus cannot be grown, Udo should
make a welcome addition to the vegetable list. It is not likely
to succeed well in the coastal plains because it is severely attacked
by rootknot. This pest destroyed over 90 per cent. of our plants
A.
i'g. Il .-Roadway planted with St. Augustine grass.
Florida Agricultural Experiment Station
up to 1912, and the rest were so weakened as to give no crop the
second year.
A temperature of 32 degrees on October 80, 1910, did not
injure the foliage or stems, but a frost of 23 degrees on Decem-
ber 2, 1910, killed the tops to the ground. On April 28, 1911,
some of the shoots were large enough to cut for use. From time
to time other shoots grew sufficiently to be tested. In 1912 no
cuttings were made, and by October 10, 1912, all the plants had
died, apparently from root-knot attack.
Deciduous Fruits.-A considerable number of varieties in
this line have been planted out and some of them are doing fairly
well. The new Chinese Persimmon known as Tampan has
fruited this year. The trees are doing well, and this will ap-
parently be an acceptable and delicious novelty in this class of
fruits. The Terrell Plum has been continued, but has not given
satisfactory crops.
Citrus Fruits.-The planting out of citrus novelties has con-
tinued, and the old orchard is kept up as much as possible. The
Experiment Station, however, is located too far north to make
it desirable to plant out an extensive citrus orchard. The hardi-
est varieties do fairly well, but even Satsuma on trifoliate stock
has been repeatedly killed back by cold in the winter. The citrus
fruits known as citranges seem to be well adapted to the condi-
tions here. Some of the oldest trees are beginning to bear fruit.
ANIMAL INDUSTRY.-The chief attention during this fiscal
year has been devoted to hog-feeding and milk production. Both
of these lines of work have progressed far enough for data to
be compiled, and bulletins will be issued durir.r 'he next fiscal
year. Many valuable data have been obtai-'d relating to the
cost of producing milk, stated in terms of the cost of forage.
A large amount of original work has been .one a!.ng this line,
since nearly all of the forage crops that are or importance to
us are different, from those grown in the North, and in many
cases their feeding value is unknown.
The work of hog-feeding with different rations and under
different conditions has been carried forward as rapidly as pos-
sible. Data are being brought together which will appear in
bulletin form during the next fiscal year. The main object of
this work is to ascertain the adaptability of different crops for
hog feeding.
CHEMISTRY.-Our chemists are giving their entire attention
to the project relating to soils and fertilizers, careful study being
made of the effects of the quantities and kinds of fertilizer ap-
Annual Report, 1912
plied to citrus trees, the effects of these chemicals on the soils
to which they are applied, and the loss of plant food through
leaching. This latter project has already given some valuable
and important results. The value of this work will increase
as time passes, and the amount of data accumulates. The water
collected from the soil tanks shows that a very large amount
of nitrogen is lost in this way, that the amount of potash that is
lost is comparatively small, and that the amount of phosphoric
acid lost is relatively very small.
ENTOMOLOGY.-The work in this subject has been confined
mainly to the study of citrus whitefly. Three species of this
pest affecting citrus are now known to be established in the
State, Aleurodes citri (citrus whitefly), Aleurodes nubifera
(cloudy-winged whitefly), and Aleurodes howardii (woolly
whitefly). Careful inquiry has been made as to the best meth-
ods of handling this pest. This work has been going on vigor-
ously, and a large amount of information has been given to the
agricultural press on the subject. Observations in connection
with the woolly whitefly have shown that a large number of
pests are parasitized, thus indicating that this species is not likely
to become seriously injurious in the State.
PLANT PATHOLOGY.-During the present fiscal year three
bulletins on citrus diseases have been issued. The first, on stem-
end rot of citrus fruits, was a preliminary report on this work as
carried out by the Experiment Station, and the second, on diseases
of citrus fruits was more or less of a final report on the work
done along this line. The bulletin on citrus scab was somewhat
of a preliminary report on this subject. All of these bulletins
contain important suggestions and instructions as to the best
known methods of controlling and combating the various troubles.
The work of the plant pathologist has been materially in-
creased by the addition of a section on vegetable diseases, special
attention being given to the study of certain little understood
diseases of the tomato, eggplant and cucumbers. Some of these
diseases appear to be distinctly different from those that have
been reported from other parts of the United States.
PLANT PHYSIOLOGY.-The studies on this subject have been
taken up from the standpoint of plant nutrition. A material
advance has been made in the understanding of the mal-nutri-
tional disease of citrus known as dieback. This disease has been
known to citrus growers for about forty years. The understand-
ing of the nutrition of citrus trees is, however, so imperfect that
no preventive measures are known that can be considered as gen-
Florida Agricultural Experiment Station
rally applicable. The annual amount of damage done by die-
back is relatively large. The problem is one requiring careful
fundamental investigation as the difficulty must be overcome by
preventive rather than curative methods.
PLANT BBEEDING.-The chief work in this project has been
devoted to the crossing of the velvet bean with other nearly
related species, and the pure breeding of the progeny. This has
been carried on for three or four years and the results obtained
are promising. Several strains from these crosses are being
bred pure, and competitive tests are being made with these new
varieties to ascertain their yields under different seasonal con-
ditions as compared with other and better known varieties. The
amount of pedigreed seed of any one of these strains is still lim-
ited, and no attempt is being made to increase it materially until
it is known which of the many promising segregates will prove
more useful than the three or four varieties already established.
A large amount of space, about seven acres, was devoted to this
breeding work this year. During the present year tests are
being made, and it is expected that in the next annual report
preliminary data can be given as to the yields of one or more
of these segregates under field conditions.
Hybridization of corn is being carried on with the view of
securing data as to the suitability of different new types of corn
for Florida conditions.
PLANT INTRODUCTION.-A large number of new plants have
been introduced from the tropics and sub-tropics. The main at-
tention of the plant introduction work has been centered on
forage crops. Thirty-two different varieties of alfalfa have
been tried out and records kept. None of these varieties seem
to show any special adaptation to our soil and climatic condi-
tions. Other legumes give larger yields than alfalfa.
Rhodes Grass (Chloris gayana), mentioned last year in the
report as a promising grass, has continued to give good results.
This grass may now be considered to have passed the introduc-
tion stage, and to have arrived at the stage where it should be
tested out in field plots. It is doing well in various localities of
the State, though some are reporting unfavorably on it.
Yokohama Velvet Bean (Stizolobium hassjoo).--This is the
least vigorous of the Stizolobiums that have been grown on the
Experiment Station grounds. Seed from Japan was obtained
through Prof. C. V. Piper of the U. S. Department of Agricul-
ture. The important quality that the Yokohama bean possesses
Annual Report, 1912
is that of early ripening, the seed coming to maturity in about 120
days. It fills an important place among our leguminous crops,
since it can be planted as a catch crop after cereals or corn and
still ripen, giving a crop that is relatively high in protein. It
also produces ripe beans at the time when stock and hogs should
be started on a fattening ration. It appears to be resistant to
root-knot and in this respect is superior to cowpeas.
Chinese Velvet Bean (Stizolobium niveum) was introduced
three years ago, the Experiment Station receiving a single seed
of this variety. Since that time it has proved that the plant
ripens early in the season, attaining maturity before there is
probability of frost in any portion of Florida. This early ripen-
ing quality makes it very desirable, especially in the northern
part of the State. It grows as vigorously as the Florida velvet
bean.
Lyon Bean (Stizolobium niveum).-The seed of this bean
was introduced from the Philippine Islands about six years ago,
and the plant has proved itself to be a very vigorous grower,
ripening at about the same time that the Florida velvet bean
ripens. Many farmers in the State consider it superior to the
latter. In our tests at the Experiment Station we find that it is
som-what more vigorous and sometimes the seed ripens earlier
than that of the velvet bean, but on the average the seed ripens
about the same time as that of the velvet bean. Taking all the
conditions into consideration it seems to us that it has no par-
ticular qualities that commend it especially above the Florida
velvet bEcn.
CO-OPERATIVE WORK.-A considerable amount of co-opera-
tive work has been carried on during the year, especially with
the Office of Seed and Plant Introduction of the U. S. Depart-
ment of Agriculture, directly with Prof. C. V. Piper.
A considerable amount of co-operative work has been estab-
lished with different farmers of the State, this work being car-
ried on in conjunction with the Extension Division of the Uni-
versity. This is an exceedingly valuable line of work, since it
enables the Experiment Station to determine the value of recently
introduced plants under the most favorable conditions. The
Extension Division, having its staff in the field constantly, is
able to get direct data as to the behavior of different plants.
CHANGES IN STAFF.-During the present fiscal year some im-
portant changes have occurred on the staff. The immediate
cause is that other institutions are able to pay from thirty-three
a. r.-2
Florida Agricultural Experiment Station
to fifty per cent. more for the services of these trained men than
we are. We shall have to endure these embarrassments from
time to time unless we either reduce the amount of work we
attempt to do and thus make available more funds for salaries,
or else increase the funds for the Experiment Station.
From July 15 to September 26, E. R. Flint served as tem-
porary Assistant Chemist, making analyses of soils and of water
secured from the leaching tanks. Dr. E. W. Berger, Entomolo-
gist of the Experiment Station since May, 1906, tendered his res-
ignation to become effective July 1, he having been appointed by
Governor Gilchrist as State Nursery Inspector. A. W. Blair,
connected with the Experiment Station since 1901, resigned his
position on October 15, 1911, to take up work with the New
Jersey Experiment Station. H. S. Fawcett, connected with the
Experiment Station since 1906, resigned his position on Febru-
ary 1, 1912, to become Pathologist to the California Horticultural
Commission. W. Voorhees resigned his position as Librarian
on June 1, 1912. J. B. Griffiths resigned his position as Labora-
tory Assistant to the Plant Pathologist on June 1, 1912, to take
up work with a phosphate company as private analyst. On July
1, 1911, F. M. O'Byrne, a graduate of Miami University, com-
menced work in the position of laboratory assistant to the Plant
Physiologist. On July 1, 1911, 0. F. Burger, M. S. graduate
of the University of Florida, began work as Assistant Plant
Pathologist. On September 17, 1911, J. R. Watson began work
in the position of Entomologist. He is a B.S. graduate of Bald-
win University, and an A.M. graduate of Western Reserve. At
the time of accepting the position he was Professor of Biology in
the University of New Mexico. On February 20, 1912, H. E.
Stevens began his work as Plant Pathologist at the Experiment
Station. Mr. Stevens is a M.S. graduate of Illinois University,
and at the time of accepting this position was Adjunct Plant
Pathologist in the University of Arkansas. On October 15, 1911,
S. E. Collison, Associate Chemist, was placed in charge of the
Department of Chemistry. On January 22, 1912, S. S. Walker, a
graduate of Stetson University and a M.S. graduate of Chicago
University, began work as Assistant Chemist
BULLETINS
The following press bulletins and bulletins, with the annual
report, were published during the year:
xviii
Annual Report, 1912
PRESS BULLETINS
No. Title Date Author
172. Bulletins and Reports on Hand--July 8, 1911........
178. Cultivation of Sweet Potatoes-July 15,1911....----.....C. K. McQuarrie
174. Choosing and Breeding Pigs--...August 26, 1911---..... J. M. Scott
175. Curing the Hay Crop.....-...September 9,1911-_C. K. McQuarrie
176. Bedding Seed-Cane_... ....-November, 11, 1911---C. K. McQuarrie
177. Storing the Sweet-Potato Crop-November 18, 1911---C. K. McQuarrie
178. Velvet-Bean Seed-----..........November 25, 1911-.-J. M. Scott
179. Pig-Feeding Experiments-......December 30, 1911....J. M. Scott
184 Pruning for Withertip and
Stem-End Rot of Citrus...---- January 13,1912-.....H. S. Fawcett
181. Bulletins and Reports on Hand_-January 20, 1912.....
182. Balanced Rations for Dairy
Cows --------------January 20, 1912-.....J. M. Scott
188. Spraying and the Citrus Purple
Scale --------------------- February, 3,1912....---H. S. Fawcett
and 0. F. Burger
184. Drying Citrus Fruits by Heated
Air --------- .....-------------March 2,1912 ....--- J. R. Benton
185. Growing Sweet Potato Draws-_March 9,1912-- ....C. K. McQuarrie
186. Corn Planting ....-------..----March 16,1912-.......A. P. Spencer
187. Young Beef the Most Profitable-April 6, 1912----........ M. Scott
188. Corn Cultivation ......--- ..-------April 13, 1912----.......J. M. Scott
189. The Small Canning Factory ....April 20,1912----.....C. K. McQuarrie
190. The Control of Thrips on To-
matoes -------------------May 4,1912...--....----J. R. Watson
19L Native Cattle Small from Lack
of Feed------------------- May 11, 1912.----....-- J. M. Scott
BULLETINS
107. Stem-End Rot of Citrus Fruits;
23 pages....................----------October, 1911 ---...H. S. Fawcett
108. Diseases of Citrus Fruits; 23
pages ---------------------November, 1911-_P. H. Rolfs,
H. S. Fawcett,
and B. F. Floyd
109. Citrus Scab; 12 pages- ---......- May, 1912 ...--- H. S. Fawcett
110. Native and Grade Cattle Breed-
ing; 12 pages ------ -------...... June, 1912----- J. M. Scott
ANNUAL REPORT for 1911; 108 pages, with index to all bulletins.
xx Florida Agricultural Experiment Station
REPORT OF AUDITOR
P. H. Rolfs, Director,
Florida Agricultural Experiment Station,
Gainesville, Fla.
SIm: I respectfully submit the following report of credits
and disbursements out of funds as follows:
Sales or
CREDITS Hatch
By Bal. July 1, 1911.. _
By U. S. Treas. for fiscal
year 1911-12 15,000.00
By Receipts-----------
Total ...$
EXPENDITURES
By salaries $-
By labor __-
Publications
Postage and stationery....
Freight and express....
Heat, light and water--
Chemical supplies--
Seeds, plants and sundry-
Fertilizers
Feeding stuffs
Library
Adams Incidental
$ 850.42
2,512.27
$ 2,862.69
Sales
$ 541.66
282.90
561.15
24.38
8.35
23.36
44.72
35.45
14.25
1.50
11.60
118.39
281.12
913.86
$ 2,862.69
15,000.00
15,000.00 $15,000.00
Hatch Adams
6,688.37 $11,661.26
2,802.92 750.87
510.34 _
375.47 52.29
271.10 169.09
171.13 59.45
.__ 392.10
245.83 361.23
273.97 9.00
1,625.09
286.52 92.08
Tools, implements and ma-
chinery 272.16
Furniture and fixtures___ 242.75
Scientific apparatus. -
Live stock ......._ _ 260.00
Traveling expenses......__. 251.42
Contingent expenses. 25.00
Buildings and land_____ 697.88
Balance _.... .05
Total $15,000.00
Very respectfully submitted,
140.61
5.40
322.52
799.76
184.21
.13
$15,000.00
K. H. GRAHAM,
Auditor
Annual Report, 1912
REPORT OF ANIMAL INDUSTRIALIST
P. H. Rolfs, Director,
Sm: I submit the following report of the Department of An-
imal Industry for the year ending June 30, 1912.
DAIRY HERD
During the year, four pure-bred Jersey heifers were added to
the herd: Oxford Lad's Jewel No. 271481, by Fontaine's Oxford
Lad No. 76627 out of Olive Leigh's Vixen No. 217827; Fox's
Primrose's Jewel No. 271802, by Fontaine's Oxford Lad No.
76627 out of Tame Fox's Primrose No. 208652; Fontaine's Fairy
Belle No. 271483, by Fontaine's Oxford Lad No. 76627 out of
Toko-fu' Nyam No. 161717; and Fontaine's Joyous Queen No.
276467, by Fontaine's Oxford Lad No. 76627 out of Fontaine's
Golden Beauty No. 225253.
These four heifers were purchased from Mr. B. Harris, of
Pendleton, South Carolina. Although they were brought in from
above the quarantine line, they have had only a mild attack of
Texas fever, from which they have recovered. At this time there
is no appearance of the fever having given them a setback. They
give promise of developing into good dairy animals.
Four heifer calves from the best cows have been retained to
take the place of some of the poorer cows in the herd. None of
the heifers raised on the farm are pure-breds. They were from
grade cows, and sired by Royal's Golden No. 84018.
Table I shows the age, breed, date at which the cows became
fresh, number of days they gave milk during the year, milk pro-
duced, amount of feed consumed, cost of feed, and value of the
milk produced.
TABLE 1
MILK AND FEED RECORD
0
0
. 4
Grade Jersey.-
Grade Jersey.
Native------
Grade Jersey.-
Grade Jersey-
Shorthorn --
Grade Jersey.-
Grade Jersey. -
FuED CONSUMX
dT" ^
1-1 IiA.'.*
'S
- ~0.4
No
4.11]
gU0
- -----. r = -r Y I
Oct. 28, 1911
Nov. 9, 1911
Aug. 23, 1911
Jan. 3, 1912
Nov. 2, 1911
Jan. 1, 1912
Sept.5, 1911
Dec. 17, 1911
2,644.7
3,246.2
2,596.0
3,219.0
2,338.2
3,008.6
1,975.0
2,050.8
901
881
906
577
892
588
928
668
2,250
2,250
2,250
1,500
2,250
1,125
2,250
1,500
$26.59
26.08
26.68
17.18
26.88
16.65
27.24
19.85
$ 92.25
118.24
90.56
112.29
81.56
104.77
68.89
71.51
$65.66
87.16
63.87
95.16
55.28
88.12
41.65
52.16
*There is no charge for labor.
& ',
12
11
18
11
12
4
3
3
091
|11
$.086
.069
.088
.045
.096
.047
.118
.081
Annual Report, 1912
This table gives in detail the returns from eight of the cows
in the dairy herd. These eight cows were not selected because
they were the best in the herd, but because they are good repre-
sentatives of the herd, freshened at different seasons of the year,
and were of different ages. The milk yield for cows Nos. 15 and
16 is low as compared with some of the other cows. These two
cows were only three years of age with their first calves, and
hence could not be expected to produce the maximum flow of
milk.
From July 1 to October 10 the cows were given a light feed
of bran and cottonseed meal. From October 10 to March 25, they
were given a full feed of bran and cottonseed meal. From March
25 to May 4, the feed was gradually reduced, and after May 4 no
bran or cottonseed meal was given.
In figuring the cost of the feed and cost of the milk per gal-
lon, the cows were only charged with the feed consumed during
the six months' test. No charges were made for labor. The cost
of labor varies in different parts of the State, as does also the cost
of summer pasture. Therefore, to get the actual cost of produc-
ing milk, each dairyman must take these items of expense into
consideration when calculating the cost of milk per gallon.
The feeds used were charged at the following prices: Bran,
$1.70; cottonseed meal, $1.50, and silage, $0.20 per hundred.
From Table I it will be seen that the rations fed were com-
posed of bran, two parts, and cottonseed meal, one part, by
weight. The amount of silage fed averaged closely 25 pounds per
day.
The milk was given a value of thirty cents per gallon. (One
gallon of ordinary whole milk weighs 8.6 pounds.)
Table II shows the weights of the cows at monthly intervals.
xxiii
TABLE II
WIMarGHTS O Cows IN DAIrY S m__
Cow No.
Date 1 2 4 6 6 7 8 9 10 11 18 14 15 16
August 1, 1911---...... -- 691 825 550 755 785 675 840 620 765 735 815 745 --- ---
September 1, 1911-. ----- 738 882 590 816 815 714 764 628 809 788 859 801 ... ...
October 1, 1911--------------- 755 887 578 815 796 726 725 620 809 781 868 808 528 -.
November 1, 1911...----------------747 893 582 1 726 790 746 753 646 848 731 900 861 556 ...
December 1, 1911 .-----. ----- 731 857 579 720 685 760 749 661 882 728 863 814 599 .
January 1, 1912----.....------------- 754 892 588 729 684 776 768 654 690 716 868 755 585 488
February 1, 1912---......-------------650 860 594 710 659 730 728 654 709 696 867 726 586 516
March 1, 1912..............----------------- 688 905 610 706 665 670 713 673 718 644 761 789 604 528
April 1, 1912---- ---- ----682 I 911 616 704 668 677 721 652 763 682 764 744 606 525
I I
May 1, 1912-----..............---------.. 709 981 658 744 716 720 780 704 775 728 766 760 640 568
June 1, 1912.........--------.......... 780, 883 I 673 764 748 736 829 675 764 746 753 798 658 578
July 1, 1912 ........- ------'--. 7-2 q36# R, 776 770 740 825 685 748 748 775 808 681 580
1 1
Annual Report, 1912 xxv
BEEF HERD
Since the last report, two Shorthorn bulls have been sold, Mr.
W. E. Bell of Trenton, Florida, getting one of them, and Mr.
James Harrison of Micanopy, Florida, the other.
STEER-FEEDING EXPERIMENT
One steer-feeding experiment was conducted during the win.
ter. In this experiment two steers were used.
The feeding test began January 2, 1912, and closed March
31, 1912, lasting 89 days. During the feeding period the steers
made a gain of 299 pounds, or an average daily gain of 1.68
pounds.
The feeds were corn and cottonseed meal, with Japanese cane
for forage. The corn and cottonseed meal were fed in the propor-
tion of three parts of corn by weight to one part of cottonseed
meal. Table III gives the results.
TABLE III
WEIGHTS AND GAINs
Pounds
Weight at beginning of feeding test, January 2, 1912 ------------- 1,835
Weight at end of thirty days ---------------......-----------....-------- 1,925
Weight at end of sixty days ---------------------------------- 2,055
Weight at close of feeding test, March 31, 1912 ------------------ 2,134
Total gain in 89 days -------------------------------------- 299
Average daily gain per head ---------------------- 1.68
FEED CONSUMED
Pounds
Corn ----------------------.......------. 2,160
Cottonseed meal -------------------------------------------- 776
Japanese cane -------_-- --- ---- ---- 4,965
CATTLE BREEDING
The work of improving the native Florida cattle mentioned
in the Reports for 1909, 1910, and 1911, has been completed.
This work was started during the spring of 1908. Fifteen native
cows were selected. These fifteen cows were separated into three
lots of five cows each. The lots were arranged as nearly equal in
size and quality as possible. The cows in Lot I were bred to a
Hereford bull, those in Lot II were bred to a Shorthorn bull, and
the cows in Lot III were bred to a native Florida bull.
From these fifteen cows, twelve calves were produced. One
Florida Agricultural Experiment Station
cow failed to breed; a second.cow was found to be in calf when
the experiment started, and was discarded; while a third cow
met with an accident and aborted. Each lot of cows and bull
was kept in a separate pen until each cow was known to be in
calf.
From the time the cows were bred until the calves were
weaned all cows were kept on the same range. In this way
each lot of calves had the same chance so far as range conditions
were concerned. After the calves were weaned, observations
were continued on only two calves from each lot of cows. After
weaning time, the calves were all kept on the same pasture in
summer, and during the winter season they were given the run
of a velvet-bean and Japanese-cane field; so that from the time
the cows were bred until the experiment closed all calves were
given an equal chance.
Table IV gives the date of breeding of each cow, and the
date when each calf was dropped.
TABLE IV
Date when cows were bred
April 18, 19(
April 24, 19(
April 28, 19(
June 10, 190
August 23, 1
May 5, 1908
July 10, 190
July 2, 1901
July 18, 1901
Date when calves were dropped
Cows Bred to Hereford Bull
)8 January 6, 1909
08 I January 10, 1909
08 January 31, 1909
8 March 20, 1909
908 June 2, 1909
Cows Bred to Shorthorn Bull
February 16, 1909
8 I April 26, 1909
8 April 12, 1909
8 April 7, 1909
Cows Bred to Native Bull
10 May
11 June
12 July
13 July
18, 1908
24, 19(08
14, 1908
20, 1908
February 24, 1909
Aborted, January 18, 1909
April 18, 1909
April 28, 1909
I
Cow No.,
I
1
2
3
4
5
6
7
8
9
xxvi
Annual Report, 1912 xxvii
TABLE V
WEIGHTS OF CALVES
Time of GRADE HEEFORDms IGRADESHORTHORNSI NATIVES
Weighing No.1. No.2. Av'ge. No.3. No.4. Av'ge. No.5. No.6. Av'ge.
Birth ------- 52 52 47.9* 52 61 56t 48 47 48.6l
Weaning time,
Oct. 28, 1909-. 265 340 352* 390 330 342t 310 325 305*
One year old-- 442 368 405 425 470 447 485 410 447
May 1, 1910-- 410 442 426 502 472 487 487 467 477
June 1, 1910-- 442 475 458 528 507 517 515 490 502
July 1, 1910-- 486 510 498 566 532 549 552 522 537
Aug. 1, 1910- 505 530 517 590 545 567 560 530 545
Sept 1, 1910-. 500 525 512 592 545 568 572 540 556
Oct. 1, 1910-- 505 545 525 565 550 557 565 550 557
Nov. 1, 1910-. 495 535 515 559 547 553 568 547 557
Dec. 1, 1910--- 490 535 512 540 530 535 560 550 555
Jan. 1, 1911--- 460 515 487 525 525 525 530 535 532
Feb. 1, 1911-- 462 542 502 537 555 546 557 542 549
Mar. 1, 1911-. 482 560 521 552 577 564 582 576 579
Apr. 1, 1911-- 507 580 543 567 600 583 610 610 610
May 1, 1911-- 535 625 580 602 610 606 650 632 641
June 1, 1911-- 540 630 585 600 600 600 640 630 635
July 1, 1911-- 595 635 615 635 610 622 675 665 670
Aug. 1, 1911-- 640 695 667 670 655 662 700 690 695
Sept. 1, 1911-- 715 730 722 737 775 756 785 767 776
Oct. 1, 1911-- 680 710 695 680 700 690 735 710 722.5
Nov. 1, 1911-- 697 727 712 682 720 701 750 745 747
Dec. 1, 1911-- 660 672 666 667 710 688 713 719 716
*Average of five calves.
tAverage of four calves.
tAverage of three calves.
Table V shows that at birth the grade Herefdrds averaged
49.7 pounds, the grade Shorthorns 56, and the natives 48.6
pounds. At weaning time, October 28, 1909, when the calves
were about seven and a half months old, the grade Herefords
averaged 351.6 pounds, the grade Shorthorns 342.5 pounds, and
the natives 305 pounds. Thus there are only slight differences
in the weights of the different lots at birth and also at weaning
time.
The weights when the animals were one year old were
quite uniform. The grade Herefords averaged 405 pounds, and
the grade Shorthorns and natives both averaged 447.5 pounds.
For the first year the grade Herefords made an average
daily gain of 0.97 pounds, the Shorthorns an average daily gain
of 1.07 pounds, and the natives an average daily gain of 1.09
Florida Agricultural Experiment Station
pounds. Therefore, there are only slight differences in the
average daily gains of the three lots.
When we compare the weights of these steers when one
year old with that of the average native steers, we find that at
one year these animals were about twice as heavy as the average
native steer of the same age.
Although this experiment indicates that the native cattle
made as good gains from birth until two and a half years of age
as did the grade Herefords and grade Shorthorns, it does no; in-
dicate that the native cattle are more profitable than grades.
The experiment does show without a doubt that by proper
selection and the supplying of an abundance of good forage dur-
ing the winter season we can increase the size of our native
stock as much as 30 to 40 per cent
On December 2, 1911, the steers were put on feed. The
feeding test lasted ninety days, closing March 1, 1912. While
on feed they were fed a ration of corn, cottonseed meal and
Japanese cane forage.
Tables VI, VII and VIII show the ration fed, the feeds con-
sumed, and the weights and gains.
TABLE VI
RATION
Corn ..---...-------------------____ ---------.. 8 pounds
.Cotton-seed meal--------- -... 4.6 pounds
Japanese cane forage--..----------------------------- 21.6 pounds
TABLE VII
TOTAL Fzm CONSUMED
Corn ..--------------------------------------_________.... 8,986 pounds
Cotton-seed meal------ -------------------------- 2,253 pounds
Japanese cane ............-----------------------------....... 11,502 pounds
xxviii
Annual Report, 1912 xxix
TABLE VIII
WEIGHTS AND GAINS IN POUNDS
No.1 No. No .o. 3 No. 4 No. 5 No. 6
Native Here- Short- Short- Native Nat.
ford horn horn
December 2,1911. Begin- 660 672 667 710 713 719-
ning of feeding test.
January 1, 1912. End of 710 723 717 769 772 785
30 days.
January 31,1912. Endof 722 757 766 827 846 813
60 days.
March 1, 1912. End of 773 784 831 886 856 893
90 days.
Total gain in 90 days--- 113 112 164 176 147 174
Average daily gain..... 1.26 1.24 1.82 1.96 1.63 1.93
HOGS
Since the last report two Berkshire sows have been pur-
chased, Hurstview Maid's Charmer 162689 and Hurstview Maid's
Charmer 2nd 162690 out of Hurstview Maid 123158 by Hurst-
view Baron Premier 152531, bred by W. N. Jones and Sons,
Montgomery, Ala. These two sows were farrowed on Novem-
ber 17, 1911. Aside from the addition of these two young sows
the herd remains the same: consisting of four old sows and one
boar.
PIG-FEEDING EXPERIMENTS
During the year three feeding experiments with pigs have
been conducted. In these tests 37 pigs were used. The pigs
were all bred and raised on the station farm.
The first feeding experiment was conducted with young
pigs that weighed about 35 pounds per head at the time the
feeding test began.
The feeds used in this feeding test were corn, shorts, milk,
and green sorghum. These feeds were fed in nearly equal
amounts. The gains produced were satisfactory. The average
daily gain per head was 0.96 pound. This daily gain was good,
considering that the pigs only averaged about 35 pounds per
head. Figuring on the basis of 1,000 pounds live weight, we
find the average daily gain per thousand pounds live weight to
be 27.8 pounds.
Florida Agricultural Experiment Station
This experiment proved satisfactory in all respects except
in the cost of producing a pound of gain. The high cost of pro-
ducing gain in this experiment was due to the milk used. Milk
is an excellent hog feed, but at twenty-five cents per gallon it
means nearly three cents per pound for the milk.
The second feeding test was conducted with ten pigs. These
pigs were much older than were those used in the preceding
test. The average weight at the beginning of the test was 99
pounds. The feeding test covered a period of 48 days, during
which time the ten pigs gained 339.3 pounds in weight. They
made an average daily gain per head of 0.79 pound. The aver-
age daily gain per head in this experiment was not so good as
in the experiment given above. The cost of the gain was over
eleven cents per pound.
An experiment with ten pigs, fed on equal parts by weight
of shelled corn and sweet potatoes, was conducted from January
16, to February 15, 1912. The average weight of the pigs at
the beginning of this test was 101 pounds. During the thirty
days, the ten pigs made an average daily gain per head of 0.65
pound. This average daily gain per head was small. When we
figure the cost per pound of gain, we find, however, that a com-
bination of corn and sweet potatoes produced cheaper pork than
any of the other feeds used.
Tables IX, X and XI show the results of the experiments in
detail.
In all of the feeding experiments conducted with pigs, the
feeds have been charged at the following prices:
Corn -------------------------------------$1.60 per hundred
Shorts ---------------------- 1.70 per hundred
Sweet potatoes ---------------. 1.00 per hundred
Green sorghum -----.....----...----- ------------- 0.10 per hundred
Milk --------------------------------------. 0.25 per gallon.
TABLE IX
PIG-FEEDING EXPERIMENT I
WEIGHTS AND GAINS
Pounds
Weight at beginning of test, June 1, 1911 (17 head)---------- 590
Weight at close of feeding test, Sept 22, 1911--------------- 2,461.6
Total gain in 114 days--------...........---- --------------------1,871.6
Average gain per head in 114 days-------------------------110.09
Average daily gain per head---------------- 0.97
Cost per pound of gain, $0.114.
Cost per hundred pounds of gain, $11.40.
XXX
Annual Report, 1912 xxxi
FEEDS CONSUMED
Pounds
Corn -.......----- ------------------------------------ 3,585
Shorts ------- ------------------------------------------- 3,105
Green sorghum ......-....------------------------------------- 3,268
Milk ---------------- -- --------------------- ------------ 3,443
TABLE X
PIG-FEEDING EXPERIMENT II
WEIGHTS AND GAINS
Pounds
Weight at beginning of test, July 18, 1911 (10 head) ------------ 990
Weight at close of feeding test, Aug. 29, 1911 ------- --1,329.2
Total gain in 43 days-..-- -- ------------------------------ 339.3
Average gain per head ------------------------------------- 33.9
Average daily gain per head in 43 days------------------------ 0-79
Cost per pound of gain, $0.112.
Cost per hundred pounds of gain, $11.20.
FEEDS CONSUMED
Pounds
Corn ----------------------------------------------------- 2,216
Green sorghum -------------------------------------------- 2,580
TABLE XI
PIG-FEEDING EXPERIMENT III
WEIGHTS AND GAINS
Pounds
Weight at beginning of test, July 18, 1911 (10 head) ----------- 90
Weight at beginning of test, January 16, 1912 ----------------- 1,010
Weight at close of test, February 15, 1912 ------------------- 1,207
Total gain in 30 days ------------------------------------- 197
Average gain per head ----------------------------------- 19.7
Average daily gain, per head------------------------------ 0.65
Cost per pound of gain, $0.068.
Cost per hundred pounds of gain, $6.85.
FEEDS CONSUMED
Pounds
Corn ----------------------------------------------------------- 505
Sweet potatoes ---------------------------------------------- 60F
YOKOHAMA BEANS
Two acres of Yokohama beans, Stizolobium hassjoo, were
grown last year. The results of the crop were very satisfac-
tory. Acre 31 (S. P. I. No. 27164) produced a yield of 1435
pounds of beans in the pod. Acre 41 (S. P. I. No. 25254) pro-
Florida Agricultural Experiment Station
duced a yield of 1381 pounds of beans in the pod. The two
acres gave an average yield of 1408 pounds of beans in the pod
per acre. The above yield is not equal to that of the velvet
and Lyon beans. But the Yokohama beans do not make the
same growth of vines as the velvet and Lyon beans. They
were planted in rows four feet apart with the plants about one
foot apart in the row. When planted at these distances the
vines did not cover more than half the ground. From the
amount of growth the vines made this year, it will be safe to
advise planting in rows two and a half feet apart and from six
to ten inches apart in the row. Planted in this way the yield
should be increased about 40 -per cent. The yield would then
compare favorably with that of the velvet and Lyon beans.
The value of the Yokohama bean does not depend entirely
upon the yield as compared with the velvet and Lyon beans. The
Yokohama bean matures in about 120 days after planting. This
means that it matures about two months earlier in the fall than
do the velvet and Lyon. This in itself is an important fact, for
two reasons. First, early maturing means that the crop will be
ripe before the caterpillars put in their appearance. Of late
years the caterpillars have caused considerable loss to velvet-bean
growers. It will mean much to live-stock men if we can pro-
duce a forage crop equal to the velvet bean without its being
injured by the caterpillars. Second, the early maturing of the
Yokohama bean ensures us an early fall crop for the feeding of
our dairy cows, hogs and cattle, which means that less purchased
feed will be needed, and that hogs and cattle can be fattened for
the market earlier in the season and at less cost than when pur-
chased feeds are used.
JAPANESE CANE
The work with Japanese cane during the year has been the
continuation of the fertilizer test, and of the cultivation test.
From the fertilizer test we have obtained no striking results,
but we are gathering information that is of such a nature as
to be of much help to us in the near future.
Table XII shows the yield per acre from the different plots
for the past three years, and the average of the three years.
Table XIII shows the density of the juice and the amount of
sugar in it.
xxxaii
Annual Report, 1912
TABLE XII
JAPANESE CANE FERTILIZER TEST
Yield Yield Yield Average of
1909, 1910, 1911, three years,
tons tons tons tons per acre
Plot I -------------------- 24.2 14.6 7.08 15.29
Plot II--------------------17.7 12.4 9.00 13.03
Plot III-------------------16.1 10.0 9.63 11.91
Plot IV ------------------- 19.1 14.4 14.36 15.95
Plot V--------------------19.5 11.8 13.56 14.95
Plot VI ------------------- 18.9 16.7 15.48 17.02
Plot VII ------------------ 16.6 14.1 14.02 14.90
Plot VIII ----------------- 27.0 16.0 14.10 19.03
TABLE XIII
ANALYSIS OF JUICE OF JAPANESE CANE
Crop 1909 Crop 1910 Crop 1911 Average of the
SI_____ three years
I Brix I Sucrose Brix ISucrosel Brix I Sucrose] Brix I Sucrose
I I I I
Plot I -------...... 16.7 11.85 15.4 11.00 14.0 9.30 15.35 10.71
Plot II ------17.2 13.50 15.4 10.85 13.9 9.24 15.50 11.19
Plot III- ... 17.7 13.75 15.3 10.50 13.6 6.12 15.53 10.15
Plot IV-- 17.4 13.65 15.4 11.00 13.5 9.00 15.43 11.21
Plot V ------..... 17.4 13.60 15.6 11.20 14.0 7.92 15.66 10.90
Plot VI .. 17.5 13.50 15.6 11.10 14.2 6.90 15.76 10.53
Plot VII -- 17.6 13.58 15.5 10.95 14.3 8.12 15 80 10.83
Plot VIII --.... 17.8 13.74 15.5 10.90 14.2 9.18 15.83 11.27
The results of the three years' work point strongly to the
advantage of using ground limestone. Plot VIII receiving lime-
stone (2000 pounds per acre) produced, on the average of three
years, two tons per acre more green forage than any other plot.
Plot VII, which was fertilized the same as Plot VIII, except that
it did not receive ground limestone, produced, on the average of
three years, 4.13 tons of green forage less per acre. Plot II,
which has received no ammonia during the three years, made
the remarkable yield of 13.03 tons of green material per acre
on an average for three years. The smallest yield on the aver-
age for three years was from Plot III, which gave 11.91 tons.
This plot was fertilized each year with dried blood and acid phos-
phate, no potash being applied. It is hard to account for the dif-
ference in yield of Plots II and III. One would naturally think
a. r.-3
xxxiii
Florida Agricultural Experiment Station
the plot receiving fertilizer containing ammonia would give a
larger yield, but such was not the case in this test.
In the spring of 1911 a second fertilizer experiment with
Japanese cane was started. Three plots were selected and were
fertilized as follows:
PLOT I
Dried blood---- -- --------------- 112 pounds per acre
Sulphate of potash.------------..........-------------........ 84 pounds per acre
Acid phosphate .........-------........--......------.... 224 pounds per acre
Ground limestone ---------..........-----.......---....... 2,000 pounds per are
PLOT II
The same as Plot I except no ground limestone was applied.
PLOT HI
Dried blood----- --------------------------- 112 pounds per acre
Sulphate of potash......------------------------ 84 pounds per acre
Ground limestone-------------------------.... 2,000 pounds per acre
Table XIV gives the results. As in the former experiment,
all indications point to the beneficial effect of the ground lime-
stone when used with a complete fertilizer. In this experiment
the use of 2000 pounds of ground limestone increased the yield
by 50 per cent. However, the increased yield from the use of
ground limestone seems to be only from the first year's crop,
as the second application of ground limestone, which was made
in the second year, did not produce the increased yield shown
by the first application.
TABLE XIV
JAPANEsE CANE FERTILIZER TEST No. 2
Analysis Yield of green material
Plot No. Brix I Sucrose Tons per acre
1----------------------... 13.8 4.7 15.56
2 ---------------------- 13.7 4.24 10.87
3 ---------------------- 13.4 4.07 11.81
CULTIVATION TEST OF JAPANESE CANE-After two years'
work on the depth of cultivation, we find that there seems to
be but little relation between the depth of cultivation and the
yield per acre of green forage. All plots were fertilized alike
and at the same time, the same formula being used each year.
Table XV gives the results. Fertilizer was applied as follows:
Dried blood------.....................------------------..... 75 pounds per acre
Acid phosphate----------------------------- 150 pounds per acre
Muriate of potash--------------------------- -- 56 pounds per acre
xxxiv
Annual Report, 1912
TABLE XV
CULTIVATION TEST OF JAPANESE CANE
Yield of green material
Plot Depth of cultivation per acre, tons
1 1910 1911 Average
1 Two inches deep --------------- 16.6 15.30 15.95
2 Four inches deep........-------------------.. 16.5 13.14 14.82
3 Six inches deep-------------------- 18.0 13.15 15.57
4 Six inches deep at first; two inches 17.0 11.49 14.24
deep afterwards.
NATAL GRASS
Two cuttings of hay were made from Natal grass during
the summer. The first cutting was made August 24. The yield
of sun-cured hay was 1156 pounds per acre. The second cutting
was made October 10. The yield of sun-cured hay was 886
pounds per acre. The total yield for the season was 2042 pounds
of cured hay per acre.
GUINEA GRASS
Two cuttings of guinea grass hay were made during the
year. The first cutting was made August 24. At this cutting a
yield of 2120 pounds of cured hay was secured per acre. The
second cutting was made November 27. This cutting gave a
yield of 1180 pounds of cured hay. The two cuttings gave a
total yield for the season of 3300 pounds of cured hay per acre.
PARA GRASS
During the year two crops of hay were cut. The first cut-
ting was made August 23. A yield of 1230 pounds of well-cured
hay was secured. A second cutting was made November 27, and
produced 1530 pounds of hay. The two cuttings gave a yield
for the season of 2760 pounds.
KuDzu
Two cuttings of hay were made during the year.
The first cutting was made July 27, 1911. The yield of
field cured hay was 730 pounds per acre. The second cutting
was made May 27, 1912. The yield of hay obtained from this
cutting was 2026 pounds per acre. This gives a total yield for
the two cuttings of 2756 pounds.
XXxv
Florida Agricultural Eperiment Station
FERTILIZING GRASSES
The Natal, guinea and Para grass were given two applica-
tions of fertilizer during the year. The first application was
given May 9, and was as follows:
Sulphate of a--onia- ..-_--------- -- 50 pounds
Sulphate of 4n50 pounds
Muriate of potash-- -----_-------- 40 pounds
Acid phosphate ---- -------------------- 80 pounds
The second application was given August 28, and was the
same as the first. The kudzu was not fertilized. Table XVI
gives the crops.
TABLE XVI
YIELDS OF HAY Piz ACRE
First cutting, Second Total yield
August 24. cutting. for season.
Pounds Pounds Pounds
Natal Grass --- --.... 1156 October 10, 886 2042
Guinea Grass ----- 2120 November 27, 1180 3300
Para Grass -.-- -- 1230 November 27,1530 2760
Kudzu -------------- July 27, 730 May 27, 1912,2026 2756
COTTON
A fertilizer test on cotton was conducted during the year.
The test was a comparison of dried blood and sulphate of am-
monia.
Plot I was fertilized as follows:
Sulphate of ammonia------------------------------- 45 pounds
Muriate of potash---------------------------------- 50 pounds
Adcid phosphate ---------------------------------- 175 pounds
Total --------...........----------------------270 pounds per acre
On an average of two plots, this produced a yield of 366
pounds of seed-cotton per acre.
Plot II was fertilized as follows:
Dried blood------------- ----------- 75 pounds
Muriate of potash ---------- -------------- 50 pounds
Acid phosphate ------.....--------...------. --- 175 pounds
Total -----------..... ..-----------.-------- 800 pounds ler acre
Annual Report, 1912 xxxvii
This produced a yield, on the average of two plots, of 312
pounds of seed cotton per acre. The difference in favor of sul-
phate of ammonia was 54 pounds of seed cotton per acre.
The results of this test would indicate that sulphate of am-
monia is a better source of ammonia for cotton than is dried
blood.
The work of selecting and improving the lint is still being
continued.
Respectfully,
JOHN M. SCOTT,
Animal Industrialist.
xxxviii Florida Agricultural Experiment Station
REPORT OF ASSOCIATE CHEMIST
P. H. Rolfs, Director,
SIR: I submit herewith the report of the work in chem-
istry for the fiscal year ending June 30, 1912.
The work here reported was carried out partly under the di-
rection of former chemist, A. W. Blair, and partly under that
of the writer. The latter is responsible for the work after No-
vember 1. The position of assistant chemist was filled by the
appointment of S. S. Walker.
CITRUS EXPERIMENTAL GROVE
DIEBACK.-The dieback in the experimental grove, comment-
ed upon in last year's report, reached a serious stage the past
year. B. F. Floyd and the writer went over the grove, carefully
noting the presence or absence of dieback symptoms in each tree.
From data thus secured it was seen that the disease was more
prevalent in certain well defined areas in the grove, while in other
portions it was nearly absent. No relationship between these
areas of diseased or healthy trees and the character of fertiliza-
tion could be noted.
An investigation of the soils of these different areas is in
progress, to determine by chemical means whether any relation-
ship between composition of soil and presence or absence of die-
back can be established.
TREATMENT OF GROVE.-The grove was fertilized as usual in
November, 1911, the application being two pounds per tree. No
fertilizer was applied this spring or summer. The trees have
been sprayed twice, in February and April, with Bordeaux mix-
ture, followed later by an insecticide.
The cultural treatment has remained the same, the grove
being plowed in spring and fall and cultivated with the harrow
at intervals up to the rainy season when cultivation is discon-
tinued, with the exception of the clean culture plots. The trees
were banked as usual during the winter months.
The trees in most of the plots have made a good growth this
spring, the new growth being free from symptoms of dieback.
In May the dead wood was cut out, and at present the trees are
looking better than they did last fall.
RAINFALL AND TEMPERATURE RECORDs.-The total rainfall
for the year was 54.77 inches. This was distributed by months
as follows:
Annual Report, 1912
July ---------- 6.25
August ---------------- 4.35
September ------------- 2.18
October------------- 3.57
November ------------- 2.91
December --------------3.88
January ------------ 7.50
February -------------- 1.69
March ----------------- 3.53
April --------------- 1.79
May ------------------- 4.45
June ------------ 12.67
The diagram gives curves showing the maximal and mini-
mal temperatures for the year by months. The unbroken lines
represent the highest and lowest temperatures for each month
3S
85
so
80
75
70
50
0
50
q10
35
30
25
7 85 O 101 12 1 23 q 5
MONTHS
Temperature from July, 1911, to June, 1912. Maximum and minimum
for each month. Solid line at Tavares; broken line at Gainesville.
xxxix
xl Florida Agricultural Experiment Station
at the Experimental Grove near Tavares, while the broken lines
represent similar data for the Experiment Station grounds at
Gainesville.
MEASUREMENT OF TREES.-In Table XVII is shown the in-
crease in growth of the stems of the trees of the grove from
June, 1909, to May, 1913, together with the fertilizer treatment
which each plot received.
It will be noted that the clean culture plots, 46 and 47, con-
tinue to hold first and second places, while the other clean cul-
ture plot, 48, has advanced during the year from seventh to
fifth place. Plot 43, which receives no fertilizer, has fallen back
during the year from ninth to twelfth place. Beyond a slight
yellow color of the leaves this plot apparently shows no ill ef-
fects from lack of fertilizer. Plot 4, which receives four times
the standard, shows no increase in diameter, and has put out but
little new growth this spring.
TABLE XVII
AvERAGE GAIN IN DIAMETER OF TREES FROM JUNE 7, 1909, TO MAY 6, 1912
?.S Fertilizer Treatment
46 32.3 Standard. Clean culture.
47 28.6 Nitrogen from dried blood. Clean culture.
85 27.5 Phosphoric acid from floats (four times standard).
41 26.9 Standard.
48 26.8 Nitrogen from nitrate of soda. Clean culture.
2 26.7 Standard.
386 26.6 Phosphoric a:id from floats (four times the amount). Cotton-
seed meal.
87 25.3 Potash from low-grade sulphate.
22 24.1 Half nitrogen cotton-seed meal, half from sulphate of
ammonia.
44 23.6 Standard.
80 23.3 Acid phosphate, nitrate of soda, and hardwood ashes.
43 23.2 No fertilizer.
42 22.1 Potash from nitrate of potash. (Balance of nitrogen from
nitrate of soda.)
12 21.7 Standard and air-slaked lime.
13 21.4 Standard. Mul:'hed.
1 21.1 One-half standard.
38 20.8 Potash from muriate.
20 20.7 Nitrogen from cotton-seed meal.
81 20.5 Standard.
8 20.4 Phosphoric acid and potash decreased by one-half.
16 20.4 Half nitrogen from nitrate of soda, half from sulphate of
ammonia.
84 20.2 Phosphoric acid from floats (twice amount in standard).
26 20.0 Phosphoric acid from steamed bone (twice amount in
standard).
6 19.8 Phosphoric acid and potash increased by one-half.
29 19.7 7% potash in June. 7%/ in October, 8 in February.
88 19.6 Phosphoric acid from floats.
28 19.5 Half nitrogen from cotton-seed meal, half from nitrate of
soda.
11 19.4 Standard and around limestone.
82 19.3 Phosphoric acid from dissolved bone-black.
19 19.2 Half nitrogen from nitrate of soda, half from dried blood.
45 19.1 Standard. Mulched.
25 18.9 Phosphoric acid from steamed bone.
7 18.6 Nitrogen and potash increased by one-half.
21 18.6 Nitrogen from cotton-seed meal. Ground limestone.
89 18.3 Standard and ground limestone.
9 17.4 Phosphoric acid and nitrogen decreased by one-half.
24 17.4 Phosphoric acid from dissolved bone-black.
14 16.9 Standard.
27 16.8 Phosphoric acid from Thomas slag. Nitrogen from nitrate
of soda.
8 16.0 Twice standard.
28 15.8 Phosphoric acid from Thomas slag (double amount). Nitro-
gen from nitrate of soda.
10 15.0 Nitrogen and potash decreased by one-half.
40 14.0 Potash from kainit.
15 13.7 Nitrogen from nitrate of soda.
17 13.2 Nitrogen from dried blood.
5 13.0 Phosphoric acid and nitrogen increased by one-half.
18 12.7 Half nitrogen from sulphate ammonia, half from dried blood.
4 8.0 Four times standard.
Florida Agricultural Experiment Station
ACIDITY OF PLOTrs.-During the year some work has been
done in a study of the effect of fertilization on the acidity of the
soil of the different plots. The intention is to carry out this
study for all the plots as time permits. In Table XVIII the
acidity of the different plots is stated in terms of parts of lime
(CaO) per million of soil, the lime-water method of Veitch being
used. The check represents the average of a number of deter-
minations on samples of soil taken midway between the trees
of a number of plots. At the point where these samples were
taken no fertilizers have ever been applied. By comparing this
check figure, 370 parts, with those representing the various
plots, an indication of the effect upon the reaction of the soil of
the various fertilizing materials can be obtained. One of the
points to be noted in the table is the alkalinity of those plots re-
ceiving lime in some form. Lime as ground limestone, air-
slaked lime, or hard-wood ashes, has proven equally effective, ap-
parently, in neutralizing the acid effect of the fertilizers.
Those plots receiving the standard formula or increases of
this formula all show comparatively high acidity. This was to
be expected from the nature of the materials used.
The average for the three standard plots is a little over 650
parts. A comparison of this figure with the 450 parts required
in plot 15 brings out the effect on the soil of the nitrate of soda,
a material which leaves an alkaline residue. This is further
illustrated by plot 27 where the nitrate of soda is used along with
Thomas slag. Compared with the check requirement of 370
parts of lime this plot shows a slight reduction in the original
acidity of the soil.
Annual Report, 1912
TABLE XVIII
LIME REQUIREMENT OF ORANGE-TREE PLOTS
I Lime
Plot required I Fertilizer Treatment
Check 370 No fertilizer.
2 525 Standard.
4 725 Four times standard.
5 550 Phosphoric acid and nitrogen increased by one-half.
6 650 Phosphoric acid and potash increased by one-half.
7 750 Nitrogen and potash increased by one-half.
11 Alkaline Standard and ground limestone.
12 Alkaline Standard and air-slaked lime.
14 750 Standard.
15 450 Nitrogen from nitrate of soda.
20 650 Nitrogen from cotton-seed meal.
21 Alkaline Nitrogen from cotton-seed meal. Ground limestone.
26 650 Phosphoric acid from steamed bone (twice amount of
standard).
27 350 Phosphoric acid from Thomas slag. Nitrogen from
nitrate of soda.
80 Alkaline Acid phosphate, nitrate of soda, hardwood ashes.
31 700 Standard.
SOIL TANK INVESTIGATIONS
FERTILIZATION.-The trees in this experiment were fertil-
ized March 14, June 10 and November 29, 1911, and April 1,
1912, according to the plan given in detail in the 1911 report.
This in brief is as follows: Each tree receives two pounds of a
standard mixture three times a year, which analyzes five per
cent. ammonia, six per cent. phosphoric acid, and six per cent.
potash. The trees in all four tanks receive their phosphoric acid
and potash from the same sources, namely, acid phosphate and
high-grade sulphate of potash, and in the same amount. They
receive also the same amount of nitrogen, but from different
sources; tree No. 1, from sulphate of ammonia; tree No. 2, the
same, with beggarweed grown in the tank during the rainy sea-
son; tree No. 3, from nitrate of soda; and tree No. 4, from dried
blood.
RAINFALL AND DRAINAGE.-The rainfall in inches from May
23, 1911, to April 13, 1912, the period covered by the results
herein reported, was 44.58 inches. During the same period
15.81 inches of water were collected as drainage. It will thus
be seen that a little over 35 per cent. of the rainfall percolated
through the soil of the tanks and was collected as drainage. By
referring to last year's report, it will be seen that about 51 per
cent. of the rainfall for the period from July 7, 1910, to May 23,
1911, was collected as drainage water. In Table 4 of the present
xliii
Florida Agricultural Experiment Station
report it will be noted that tank 2, on which beggarweed grew
during the rainy season of 1911, shows a smaller amount of
drainage than any of the others. The amount of drainage from
tank 2 is 31.5 per cent. of the total rainfall. The average for
the other three tanks is 86.7 per cent. These figures show the
added demands of a growing crop on the soil moisture.
TABLE XIX
COMPOSITION OF DRAINAGE WATER-PARTS PER MILLION
July 13, 1911-April 18, 1912
TANK I
July 13--- 73.9 .09 .02 37.2 6.6 4.7 .11 24.0 1.3 13.51 11.1 6.1
Aug. 23 -- 68.9 .10 .041 80.7 6.8 22.2 .12 25.9 1.5 22.71 19.4 6.7
Sept. 5--- 128.4 .13 .06 160.6 7.4 63.0 .12 21.8 5.3 56.3 42.7 7.1
Nov. 22 .-- 139.2 .19 .01 268.5 7.0i 111.9 .11 23.1 9.3 93.3 65.9 24.3
Jan. 8 ---- 149.0 .10 .04 240.9 7.31 166.7 .12 19.6 16.3 109.7 63.6 23.3
Mar. 12 -- 152.1 .21 .031 166.4 8.1! 292.8 .13 15.1 22.9 135.81 71.5 33.0
Apr. 13--- 99.4 .10 .061 173.6 11.11 279.8 .19 16.1 29.6, 118.2j 64.11 19.3
TANK II
July 13 --- 94.1 .11 .01 68.8 6.0 2.8 .08 17.8 2.1 22.1 11.2 4.4
Aug. 23 -- 96.7 .12 .12 192.9 10.8 2.2 .09 21.9 4.3 56.3 27.5 6.7
Sept. 5 -...- 47.9 .09 .07 808.4 10.0 10.7 .08 29.5 5.8 89.9 47.1 8.3
Nov. 22 --- 112.0 .27 .02 895.9 12.8 96.0 .11 19.2 6.9 129.3 73 3 54.1
Jan. 8...-- 187.5 .10 .02 408.8 18.4 218.8 .10 19.9 20.8 176.3 97.3 37.4
Mar. 12 -- 187.2 .30 .03 140.4 9.7 288.0 .12 15.4 29.0 144.7 55.8 17.2
Apr. 13--- 97.6 .12 .06 109.5 11.8 278.2 .18, 20.0 36.6 103.9 49.5, 16.0
July 13-.. 109.5
Aug. 23 -- 137.9
Sept. 5--- 130.4
Nov. 22-.. 136.0
Jan. 8-... 134.8
Mar. 12 -- 136.5
Apr. 13--- 102.2
92.6
262.8
689.7
716.7
434.9
82.4
149.8
TANK III
7.0 2.3 .08
10.1 2.2 .10
14.8 57.9 .09
13.7 184.1 .11
10.5 360.4 .09
6.1 338.8 .09
10.1 210.4 .15
TANK IV
July 13--- 98.0 .13 .01 70.0 5.4 14.6 .12j 26.1 3.81 19.41 20.4 11.n
Aug. 23-- 112.6 .13 .02 163.3 13.8 9.6 .10 24.7 481 3R 9 3R S 143
Sept. 5-.. 187.7 .151 .09 384.0 27.1 50.0 .12 18.1 6.1 110.3 88.21 18.8
Nov. 22--- 135.4 .301 .01 541.6 29.8 249.8 .13 28.8 6.1 1248 140 0 55.1
Jan. 8....- 126.5 .21 .02 326.6 16.8 459.4 .09 29.3 8.5 200.4 132.7 84.8
Mar. 12 -- 140.2 .30 .03 65.2 8.8 346.4 .12 25.5 15.8 1225 77.3 27.8
Apr. 13--.- 88.9 .12 .01 21.2 12.1 242.6 .19 24.4' 22.4 87.7 39 21 17.0
24.1
67.6
108.0
102.7
81.2
54.4
69.4
19.9 8.7
49 6 48.4
74.9 204.8
62.2 302.6
46.6 302.8
26.4 144.8
28.9 84.7
Annual Report, 1912
COMPOSITION OF DRAINAGE WATER IN GRAMS
July 13, 1911-April 13, 1912
5-
Date .i I
TANK I
July 13 -- 73.9 2.8 .008 0.4 1.77 0.1 1.0 0.8 0.5
Aug. 23.--- 63.9 5.2 .008 1.4 1.66 0.1 1.5 1.2 0.4
Sept. 5 ....-- 128.4 20.6 .015 8.1 2.80 0.7 7.2 5.5 0.9
Nov. 22--- 139.2 37.4 .015 15.6 3.22 1.3 13.0 9.2 3.4
Jan. 8---- 149.0 35.9 .018 24.8 2.92 2.4 16.4 9.5 8.5
Mar. 12--- 152.1 25.3 .020 44.5 2.30 3.5 20.7 10.9 5.0
Apr. 13---. 99.4 17.3 .019 1 27.8 1.60 2.9 11.8 6.4 1.9
Total-.... --- 805.9 1 144.5 | .103 I 122.6 1 16.27 11.0 1 71.6 I 43.5 1 15.6
TANK II
July 13--- 94.1 6.5 .008 0.2 1.63 0.2 2.1 1.1 0.4
Aug. 23--- 96.7 18.7 .009 0.2 2.12 0.4 5.4 2.7 0.7
Sept. 5---- 47.9 14.5 .004 0.5 1.41 0.3 4.3 2.3 0.4
Nov. 22.--- 112.0 44.3 .012 10.8 2.15 0.8 145 8.2 6.1
Jan. 8 ..-- 137.5 56.1 .014 30.1 2.73 2.8 24.2 13.4 5.1
Mar. 12-. 137.2 19.3 .017 39.5 2.11 4.0 19.9 8.1 2.4
Apr. 13--- 97.6 10.7 .018 27.1 1.95 3.6 10.1 4.8 1.6
Total ...--- 723.0 [ 170.1 1.082 I 108.4 | 14.10 | 12.1 I 80.5 I 40.6 1 16.7
TANK III
July 13 -- 109.5 10.1 .009 0.3 2.13 0.3 2.6 2.2 1.0
Aug. 23-.. 137.9 50.0 .014 0.3 2.77 0.7 9.3 6.8 6.7
Sept 5- -- 130.4 89.9 .012 7.6 2.18 1.2 14.1 9.8 26.7
Nov. 22.-- 136.0 97.5 .015 25.0 3.17 2.3 13.9 8.5 41.2
Jan. 8 .... 134.8 58.6 .012 48.6 3.87 4.2 11.0 6.3 40.8
Mar. 12 .- 136.5 11.3 .012 45.6 2.73 3.9 7.4 3.6 19.7
Apr. 13---. 102.2 15.3 .015 21.5 1.78 4.1 7.1 3.0 8.7
Total .--... 887.3 1 332.7 I .089 1 148.9 f 18.63 1 16.7 I 65.4 I 40.2 1144.8
TANK IV
July 13 93.0 6.5 .011 1.4 2.43 0.4 1.8 1.9 1.1
Aug. 23-- 112.6 18.4 .011 1.1 2.78 0.5 4.1 4.0 1.6
Sept. 5 .... 137.7 52.9 .017 6.9 2.49 1 0.8 15 2 12.1 2.5
Nov. 22_. 135.4 73.3 1 .018 33.8 3.83 1 0.8 16.9 19.0 7.5
Jan. 8... 126.5 41.3 I .011 58.1 3.71 I 1.1 25.3 168 10.7
Mar. 12-- 140.2 9.1 .017 48.6 3.57 1 2.2 I 17.2 108 3.8
Apr. 13-- 88.9 1.9 .017 21.6 1 2.17 I 2.0 7.8 3.5 1.5
Total --.... 834.3 1 203.4 | .102 1 171.5 I 20.98 7.8 I 88.3 1 68.1 1 28.7
COMPOSITION OF DRAINAGE WATER.-Seven collections of
water have been made since May 23, 1911. The results of the
analyses of these samples are given in Table XIX as parts per
million of water.
Loss of Nitrogen.-As before stated, the trees were fertil-
ized for the first time on March 14, 1911. It was not until the
Florida Agricultural Experiment Station
collection of July 18, 1911, that the increased nitrogen concen-
tration of the water from tank 3 indicated that the nitrogen of
the nitrate of soda was leaching through. In the other three
tanks an increased nitrogen concentration is not apparent until
the collection of August 23. The maximum is reached in tank
2 in the collection made on January 8, 1912; in the other tanks
it occurs on November 22, 1911.
The great ease with which nitrate of soda leaches from the
soil is clearly shown in the results on tank 3 in Table XIX. The
same is shown perhaps more clearly in the latter half of this
table, where the results are calculated to grams and show the
actual amount of material in the drainage water. The total loss
of nitrogen (calculated as NO.) is over twice as great where
nitrate of soda is used as where sulphate of ammonia is used
as the source of nitrogen. The loss is much greater also when
compared with dried blood.
It should be noted that nearly all the nitrogen recovered
in the water from all four tanks is in the nitrate form, the
amount of ammonia as such being extremely small, thus indicat-
ing the complete nitrification of the sulphate of ammonia and
dried blood.
Again the results appear to indicate that the nitrogen of
dried blood under certain conditions may be more subject to loss
than is that of sulphate of ammonia. It would appear that the
nitrification of the dried blood has proceeded at a more rapid
rate than that of the sulphate of ammonia.
Loss of Potash.-The amount of potash in the drainage
water has increased considerably over the results given in last
year's report. By referring to Table XIX it will be noted
that with one or two exceptions there is a constant increase in
the amount right up to the last collection.
Averaging the amount lost from the four tanks in the seven
collections here reported, we find that it is four times the
amount lost in the first eleven collections as given in last year's
report. Even then, however, the actual loss of potash is small,
indicating so far that most of it is held, at least temporarily, in
this soil.
Loss of Phosphoric Acid.-Taking the results given in last
year's report together with those given in Table XIX as a whole,
it will be seen that there is a gradual decrease in the amount of
phosphoric acid in the drainage water until the collections of
March 15 and May 23 are reached. With the collection of July
13 there begins an increase again, the highest results being for
Annual Report, 1912
the last collection of April 13, this increase evidently being due
to the acid phosphate applied. However, the actual amount of
phosphoric acid coming through remains extremely small, the
amount for the seven collections here reported being less than
half the amount obtained in the first eleven samplings.
Loss of Other Constituents.-Of the other constituents re-
ported upon, lime and magnesia are the most important from
the standpoint of soil fertility. Both these substances continue
to leach through in fairly large quantities, much of the lime un-
doubtedly coming from the calcium sulphate applied in the acid
phosphate. That this is true is shown also in the large amount
of sulphates obtained.
In tank 3 the effect of the nitrate of soda, a material which
tends to give an alkaline reaction to the soil, is apparent in the
smaller amount of lime and magnesia which leached through.
TABLE XX
COMPOSITION OF SOIL USED IN TANK EXPERIMENT
Results Calculated to Percentages on Air-Dry Soil
inches N PO. KO CaO MgO NaO0 SO.
0- 9 .0542 .114 .048 .310 .216 .127 .039
9-21 .0225 .099 .037 .280 .157 .173 .026
21-33 .0131 .089 .045 .275 .154 .196 .025
33-45 .0086 .082 .032 .230 .150 .310 .030
COMPOSITION OF SOIL USED IN TANKS.-During the year an
analysis of the soil used in the tank experiment has been made.
The composition of this soil is shown in Table XX.
During the year four more tanks have been put in place
and were opened to the rainfall in April. Trees will be set in
these tanks this winter. The first samples of water from this
set of tanks were collected on June 11, 1912, and are now being
analyzed.
Respectfully,
S. E. COLLISION,
Associate Chemist.
Florida Agricultural Experiment Station
REPORT OF ENTOMOLOGIST
P. H. Rolfes, Director,
SIR: I submit herewith the report of the work in the De-
partment of Entomology for the year ending June 30, 1912.
THE "NATURAL MORTALITY" OF THE WHITEFLY
On a majority of leaves heavily infested with whitefly one
finds from a few to sometimes a large majority of the larvae
dead, and of a color varying from dull white to deep brown.
These larvae, which have been killed by neither of the Ascher-
sonias, nor by the brown fungus (Aegerita webberi), nor by
the cinnamon fungus, have been designated in Florida literature
as the victims of "natural mortality." It was to determine the
cause of this mortality and to investigate the practicability of
using the disease-causing organism, if such was found, that
this study was undertaken. That the trouble is contagious can
be readily inferred from a study of its distribution in a grove
or nursery row. In such situations it is particularly abundant
in patches in the orchard or nursery. That is, it spreads from
centers of infection. It may even be abundant on a few leaves
of a small plant in the nursery row, and nearly absent from other
leaves on the same plant. On some leaves it may kill as high as
90 per cent. or more of the larvae, but from 10 to 30 per cent. is
much more common.
MICROSCOPICAL INVESTIGATIONS.-As a preliminary, the dead
larvae were examined to determine if mycelia of fungi were pres-
ent, and, if so, in what proportion of the dead larvae. By teas-
ing up dead larvae, fungus filaments were found; but there was
difficulty in deciding whether the fungus was growing in the
interior of the larvae, or was merely a superficial growth on
the dead organism. To determine this point, material was se-
lected showing all stages of the progress of the disease; from
individuals showing a mere white edge, to those completely dry
and papery. Over one hundred individuals were sectioned and
examined. The dead larvae were fixed for 24 hours in solution
of chromic and acetic acids (medium strength), run up through
a series of alcohols into xylol and paraffin, and sectioned. The
sections were stained on the slide with Delafield's haematoxylin,
and eosin or carbolfuchsin. Fifty per cent. of these dead larvae
showed fungus filaments present in the interior. Of the re-
mainder, many which had been regarded as probably in the first
xlvii
Annual Report, 1912
stages of infection, were found to have been merely preparing
to molt. This was shown by the double integument of the in-
sects; the new coat forming under the old body-wall. In some
sections the fungi were seen actually breaking through the body-
wall of the insect. Some healthy looking individuals were sec-
tioned as checks. No fungus filaments were found in or on them.
CULTURES.-Whitefly larvae were taken from infected leaves
and divided into two lots. Those in one lot were treated with a
one-tenth per cent. solution of mercuric chloride to sterilize the
outside. They were in this liquid from one to thirty seconds.
The other lot was untreated. Cultures on regular agar (one per
cent. acid to phenol-phthalein) were then made, both by the
streak method on slants in test-tubes, and by shaking up in a
test-tube of warm, but not hot, agar, and at once pouring into
petri dishes. In the latter case some of the larvae were poured
whole, and some were first cut into pieces.
From these first cultures, sub-cultures were made, and then
others, until a pure culture was obtained. Some of these pure
cultures were then transferred to sweet potato, and these were
used for spraying experiments. (See below.)
Sr -4
xlix
Florida Agricultural Experiment Station
TABLE XXI
COLONIES O ORGANISMS ISOLATED FROM VICTIMS or "NATURAL MotALITT
Colonies with
o Sal ... ilS
V5 .5 5
LO(3 W 3, a. C3 0 U,
Feb. 28-- White 38 37 8 Yes 34 0 20 0 16 0
Mar. 4 White 6 6 65 Yes 1 0 1 0 0 0
Mar. 4 .- White 12 11 0 Yes 0 0 8 0 0 0
Mar. 20 White 8 8 4 Yes 4 1 2 0 2 0
Mar. 20 White 8 3 1 Yes 2 1 2 0 0 0
Mar. 20 White 6 6 1 Yes 5 0 5 0 0 0
Mar. 20 White 7 7 3 Yes 4 1 3 0 2 0
Mar. 20- White 7 7 5 Yes 2 2 2 0 1 0
Mar. 20- Brown 12 12 2 No 10 10 0 1 0 0
Mar. 20 Brown 13 13 4 No 9 9 0 0 0 0
Mar. 20- Brown 13 13 8 No 10 5 0 0 2 0
Mar. 20 Brown 12 12 6 Yes 6 0 5 0 0 0
Mar. 20 Brown 12 12 4 Yes 8 0 8 0 0 1*
Mar. 20- Brown 12 10 2 Yes 8 0 8 0 2 0
Mar. 20 Brown 18 17 12 Yes 5 0 5 0 0 0
Mar. 20. Brown 8 8 8 Yes 6 2 5 0 1 0
Mar. 20 Brown 18 18 6 Yes 7 0 7 0 0 It
Mar. 20 Brown 18 18 4 Yes 14 1 14 0 0 it
Mar. 20 Brown 10 10 1 Yes 9 0 9 0 2 1t
Total-.-...... 128 1223 | 69 -i48 182 104 28 |I 4
Percent- I I
age....-- ..----. 100 98 80 ---- 68 14 46 0.4 12 1.8
*Tan color.
tWhite.
The results of one typical series are given in the Table XXI.
Microcera appeared in nearly 98 per cent. of the colonies (237
out of 242). Sixty-nine of these (28 per cent.) were pure cul-
tures of Microcera. One hundred and four of the mixed colo-
nies after 20 days showed a brown fungus, much of which at
least was Cladosporium. This fungus came up slowly, not ap-
pearing in many of the colonies for the first week. It is to be
noted that in the unsterilized material this fungus did not de-
velop, probably being choked out by the more rapidly growing
Penicillium, which was much more abundant than in the steril-
ized material. A bacterium producing yellow colonies appeared
in 28 cases, one being a pure colony.
In view of the known pathogenic nature of Microcera, these
Annual Report, 1912
figures leave little doubt as to the cause of the disease known as
"natural mortality."
It would seem that, in a majority of cases, this fungus does
not develop sufficiently on the whitefly larvae to produce the
characteristic white fringe which has given it its name of "white-
fringe fungus."
MICROCERA ON ADULTS.-In October, 1911, a rather severe
infection was observed in adult whiteflies (Aleurodes citri) in
a tent or greenhouse consisting of a frame work covered with
canvas, belonging to the Department of Vegetable Physiology of
the Station. The roof had not been on this tent for some months,
only the walls being covered. Many dead winged whiteflies were
observed on the under side of the leaves. Under a microscope,
fungus filaments could be found over all of the leaf. Entangled
among the filaments were many unhatched eggs which were
shriveled and apparently parasitized by the fungus. These, to-
gether with empty egg cases of whitefly and of mites, gave a
granular or mealy appearance to the leaf. A dozen cultures on
agar were made from as many of these dead adults. Microcera
appeared promptly in all of them, developing its characteristic
flocculence, several-celled curved spores, and delicate pink col-
oration when grown in the dim light. There continued to be
much natural mortality among the larvae here all winter, and
in January a few adults emerged and were attacked by the
fungus. On May 4 there were again a few dead adults sticking
to the leaves. The remnant of the April brood had just com-
pleted its flight. On none of these adults or larvae did the char-
acteristic white corona-like fringe develop, but on a few purple
scales (Lepidosaphes beckii) on the same leaves, it was well de-
veloped. It would seem that the corona, so characteristic on
scales, does not often develop on the whitefly. Perhaps this is
because of the smaller amount of food present.
SPRAYING EXPERIMENTS.-As stated above, cultures of these
fungi isolated from agar plates were grown on sweet potato.
Some of these cultures were taken from the larvae, and some
from the adults mentioned in the last section. From time to
time during the winter of 1911-1912 these cultures were sprayed
on to some nursery stock in the Station horticultural grounds.
The method used was to make an aqueous suspension of the spores
by stirring up a culture in water and then straining through a
rather coarse sieve. During the winter it was not possible to
find any plants which did not already have a goodly sprinkling
lii Florida Agricultural Experiment Station
of "natural mortality," hence it was necessary to use infected
stock, first getting a more or less accurate estimate of the mor-
tality present at the beginning of the experiment on both the
sprayed plots and on neighboring plots left for checks. This
number was compared with similar estimates made from time
to time on both the sprayed portion and on the check. Each
estimate was made by taking from twenty to forty representa-
tive leaves from each plot and determining by counting the per-
centage of mortality, and also by a careful survey of each plant
on the plot.
The results of these experiments were not very conclusive,
as the possible percentage of error due to the original uneven
distribution of the fungus was high. Nevertheless, in most of
the sprayed plots there seemed to be a slight rise in the "natural
mortality" after the spraying, and on some the amount was
doubled.
TABLE XXII
RESULTS OF SPRAYING WITH MICROCERA
Date Number of Total number
counted. leaves of larvae Per cent. dead
1912 Sprayed Check Sprayed Check Sprayed Check
May 26---....... 6 6 172 235 12.0 6.0
May 80--------....... 21 20 447 753 6.2 3.5
May 30-------- 14 15 211 20 8.3 2.35
May 81----....... 52 52 1293 1976 5.1 2.7
May 81-.....------ 833 48 212 692 6.5 4.2
June 3 ----...... 12 16 142 488 9.0 5.7
June 3 ----....... 15 18 103 224 8.0 3.5
With the second generation of larvae in April, a better op-
portunity was offered. The trifoliate orange had put out some
fresh green leaves by the time the first generation of adults were
emerging, and on this fresh material many eggs were deposited.
The resulting larvae were at first entirely free from "natural
mortality." Spraying the spores of Microcera on to these re-
sulted in about doubling the amount of "natural mortality." The
results of the spraying on May 21, which were the most marked,
Annual Report, 1912
are given in Table XXII. This proportion held good until early
June, when a protracted rainy spell so increased the "natural
mortality" over the whole plot as to swamp the comparatively
slight rise in the sprayed plots.
COLOR CHANGES.-The color of the dead larvae, as has al-
ready been mentioned, varies considerably, some being dark
brown, others quite light. However, there are all gradations
between these two extremes. Some observations were carried on
throughout the entire winter to try to determine the cause of this
variation. It was thought that the difference in color might in-
dicate a difference in causal agent or a mixed infection. The
cultures, however, did not bear out this theory. Observations on
the trifoliate stock showed pretty conclusively that the white
individuals owed their color to weathering. The freshly killed
larvae are olive-brown, often with a distinct reddish tinge. As
they get older they fade. Many, however, drop off before they
have weathered to a very light color.
SUMMARY.-1. The disease known as "natural mortality"
seems clearly to be due to the fungus we have been calling Micro-
cera or the white-fringe fungus, which often does not develop
sufficient growth of filaments to form the characteristic fringe.
2. Although some spraying experiments resulted in a con-
spicuous rise in the amount of "natural mortality," the increase
over the amount in the check plots was usually not nearly so
marked as has usually attended the introduction of the red
Aschersonia or the brown fungus (Aegerita).
3. It would seem that particular weather conditions (damp
and coolness) are necessary for the rapid spread of the Micro-
cera, as is also a more or less crowded condition of the larvae on
a leaf.
4. This fungus does not seem to do as thorough work in de-
stroying all larvae on the leaf as does the brown fungus; but, on
the other hand, it is more generally present on whitefly in dif-
ferent groves and nurseries.
5. Because of these facts it is probable that spraying
this fungus alone into trees infested with whitefly will not have
as marked effects as in the case of the red fungus (Aschersonia),
or the brown fungus (Aegerita). On the other hand, it probably
would be an excellent plan to include cultures of Microcera or
larvae showing "natural mortality" when spraying with the other
fungi.
Florida Agricultural Experiment Station
THE SPREAD AND PABRIITATION OF ALUBODES HOWAMHn
PRESENT STATUS OF ALEURODES HOWARDu (WooLLY WHITE-
FLY) IN FLORIDA.-This insect, which was introduced into Tampa
(doubtless from Cuba) three or four years ago has caused some
apprehension because of the evil reputation of its very close rela-
tive, A. citri. Two trips were made to Tampa and the St. Peters-
burg region to determine the extent of its spread, the degree of
damage wrought (that is, the severity of infestation), and its
parasites and other natural enemies.
Fig. 1.-Woolly Whitefly (Aleurodes howardii) on orange leaf, from Tampa.
Tampa.-The woolly whitefly is to be found in practically
all the citrus groves in and about the city. Many of the more
or less neglected trees in the door-yards show well-developed
colonies. A single tree in Ybor City, probably two miles from
any grove, and perhaps a mile from its nearest neighbor, showed
a heavy growth. The neglected trees in the grounds of the
Tampa Bay Hotel, probably where the woolly whitefly first ob-
tained its foothold in Florida, show a dozen or more colonies per
tree. The larvae have a marked tendency to occur in groups of
from one dozen to three or four dozen, occupying several square
inches of the surface of the leaf. It is these groups that we
have in mind when we speak of colonies. In the larger, well-
cared for groves around the city, the woolly whitefly is not as
numerous, only a few trees showing colonies; but it was found
in practically all groves visited, which included the R. S. Wilder
grove and J. M. Baker grove on the street car line to the Sulphur
Springs, and others in that neighborhood. A. howardii also oc-
curred in E. W. Aman's grove in Ybor City. At Limona, in a
grapefruit grove, there was a heavy infestation; but other groves
Annual Report, 1912
in the vicinity did not show any. In Lakeland (which seems
to be the extreme eastern limit of this species in this part of
Florida) there was a light infestation on a small door-yard grove
at the corner of Massachusetts avenue and Lemon street. Other
groves visited there, as those of Angus Biewer and George S.
Smith, did not show any.
St. Petersburg.-In the door-yard trees in the city the woolly
whitefly was generally distributed, and was common in the
grove of Mrs. Williams on North Second Street (where also was
a lively colony of Icerya purchase). The woolly whitefly appar-
ently has not as yet spread into the larger groves outside of the
city. A number of the groves on the car line running northwest
of the city, and also on the Passagrille line (including the "Ideal
Grove" of Mr. G. W. Meares), were visited and found free
from it
Arcadia was visited and the fine grove of Mr. Thomas, but
none were found. On June 1 it was sent in from Terra Ceia,
This material contained many already emerged adults. This
would indicate that its swarms are a little later than those of
A. citri, which had almost disappeared at Gainesville at that
date. The undescribed adult male was obtained from this ma-
terial. It has been reported by Back (Canadian Entomologist,
May, 1912,) as occurring in Ft. Myers, and also at Miami. The
latter at least is probably a separate importation having no con-
nection with the Tampa infestation.
SEVERITY OF THE INFESTATION AND INJURY DONE.-As com-
pared with that of A. citri the infestation is by no means severe,
although the insect makes a big show on account of its woolly
secretion. There were in no case as many larvae per leaf as is
the case with A. citri, and comparatively few of the leaves on
the trees bore colonies. It was rather hard to judge the amount
of honey-dew excreted on account of the fact that A. howardii
was in no case found in pure colonies; but judging from the ap-
pearance of the leaves directly under a colony, it would seem
that there is much honey-dew excreted.
PARASITES.-Attention was given to the insect in relation
to the parasitic fungi. Although both the red and yellow Ascher-
sonia were observed on A. citri on the same trees, and in a few
cases on the same leaves, no cases were seen of the fungi develop-
Florida Agricultural Experiment Station
ing on A. howardii. Back, however, states that the red Aseher-
sonia occurs on this species in Cuba. As both visits were made
Fig. 2.-Woolly Whitefly with red fungus, from Cuba.
in winter when the fungus was not very active the failure to ob-
serve it on A. howardii was by no means conclusive. Director
P. H. Rolfs found the red fungus attacking A. howardii in groves
at Santiago de las Vegas, Cuba, during May, 1912. (See Figure
2.) On the other hand, this species was in all cases heavily para-
sitized by some hymenopterous parasite, probably a chalcid.
From 50 to 98 per cent. of the individuals in different colonies
showed the oval exit holes of these parasites. The parasite
itself was not found. The determination of the extent of para-
sitization was not an easy matter, as it was in most cases neces-
sary to remove the woolly secretion to see the exit hole, and even
to remove the insect and examine it under a microscope before
this point could be definitely determined.
The results of some of the counts are given below, together
with the localities.
Annual Report, 1912
TABLE XXIII
Percentage Percentage show-
showing exit ing exit holes
Date, Number holes of of the aleuroid,
Localities 1912 counted the parasites i. e., emerged
Grounds of the Tampa
Bay Hotel ----- Jan. 31 40 98 Too early
Wilder Grove ---------- Jan. 31 74 50 Too early
J. M. Baker's Grove .--- Feb. 1 100 68 Too early
Gus Caden, 1312 Mich.
Ave. -------- Feb. 1 100 64 Too early
Tampa Bay Hotel------.. Mar. 12 85 87 None
Aman's Grove, Tampa
(Ybor City) -------- Mar. 12 86 68.6 11.6
St. Petersburg --------- Mar. 14 220 71.8 2
Total of last three- ------- 391 74.4 4
Back also noted this parasitization in Cuba, and also failed
to find the parasite.
SUMMARY.-1. The insect has spread quite widely since its
introduction and has been freshly introduced at Miami, and pos-
sibly at Ft. Myers.
2. In most cases the infestation is very light, as compared
with that of A. citri.
3. No parasitic fungi were found on the species during the
winter, indicating that it is not as subject to fungus attack as
is A. citri.
4. The insects were heavily parasitized (74.4 per cent.)
by some insect, probably a chalcid; also 21.6 per cent. had failed
to emerge for some unknown reason. Less than 4 per cent. had
emerged.
OBSERVATIONS ON THE STATUS OF WHITEFLY AND FUNGI IN VA-
RIOUS GROVES
This work had been carried on by E. W. Berger for several
years, and was taken up by the writer in September, 1911.
HAMPTON'S GROVE (Gainesville).-This grove was visited in October,
1911. and every month or six weeks throughout the year. In the latter part
of 1911, the grove was very sooty, and had a heavy infestation of whitefly.
But there was an abundance of fungi present especially of Aegerita. On
December 19, fifty leaves were collected at random from this grove and
the larvae counted. They were found to have an average of 70.6 live larva
Florida Agrioultural Eaxperiment Station
per leaf, and 195 dead larva. One hundred and twenty of these larva had
well-developed pustules, mostly of Aegerita, while 74.6 per cent. did not show
pustules. Many of the latter were undoubtedly killed by Aegerita, and
others were the victims of Microcera ("natural mortality"). There was
also an average .of 82.4 empty pupa-cases per leaf. It is thus seen that 40
per cent. of the larva showed fungus putules, and Microcera and other
fungi had killed most of an additional 24.8 per cent. Doubtless many of
these, and all of the empty pupa-cases, belonged to the third (September)
generation. The crop of fruit was light.
There was a very light bloom in April and none in June. On June 18,
the grove was visited. The trees were fairly black, and there was much
whitefly in evidence, especially in the Satsuma grove. Although it was at
the beginning of the rainy season, the fungi had commenced to develop,
and the indications were that there would be a heavy growth of fungus.
The grove had neither been cultivated nor sprayed.
GRAVES' GROVB (Gainesville).-This Satsuma grove was visited in Sep-
tember, 1911, and quite regularly throughout the season. In September the
trees and fruit (of which latter there was a heavy crop) were fairly black
with sooty mold; but there was a heavy growth of parasitic fungus, especi-
ally the Aegerita.
By December the fungi had almost wiped out the whitefly. The trees
were cut back during the winter. In March the grove was visited and
whitefly found to be very scarce. The remaining old leaves did not show
one live larva per ten leaves.
The brown fungus had all but annihilated the whitefly in this grove.
No insecticide was used.
STEVENS AND MONROE's GRovE (Daytona).-This grove was visited in
October, and again in November, 1911. There was much whitefly in both
groves, but also much fungus, which was keeping the whitefly well in hand.
The department of plant pathology had previously done some spraying
here, as also at Winter Park and Orlando, and an opportunity was given to
observe the effect of the materials used on whitefly and scales.
On trees sprayed with Yothers' "Formula Four" there was practically
no whitefly or scales. The trees sprayed three times with a heavy applica-
tion of this heavy-oil insecticide showed, at the time of our first visit, fruit
which was small and green as compared with the check; but they seemed
to have recovered somewhat at the time of our second visit in late Novem-
ber. Those sprayed with Schnarr's insecticide showed very few scales or
whitefly.
Those sprayed with lime-sulphur showed much fewer whitefly and scales
than the checks. A rather surprising observation was that the fruit on
these trees was larger and markedly riper than on the checks. Similar
results have been reported with this spray on peaches and other crops.
Three trees sprayed with Bordeaux mixture showed an immense increase
in scale insects due to the killing of the parasitic fungi. So heavy was
the infestation that the trees were nearly killed. On April 10, 1912, the
grove was again visited. The trees were in much better shape and there
was an abundance of the scale fungi in evidence.
At this time there was a heavy swarm of whitefly in the older grove,
but there was a good sprinkling of the brown fungus present and some of
the red Aschersonia.
At this grove a large number of eggs and some larva were found on
Ptelea trifoliata, a new host-plant.
RONNOC GROVES (New Smyrna).-These groves were visited in October,
1911. The trees were comparatively free from sooty mold, and the fruit
bright. There was some whitefly in evidence, however, and the manager
was having the grove sprayed with a heavy-oil insecticide. The whitefly
was abundant in one corner of the Jungle Grove.
On April 9, 1912, the grove was again visited. There was a heavy
swarm of whitefly in the part of the Jungle Grove that had become infested
the previous year, and a lighter infestation throughout the grove.
Iviii
Annual Report, 1912
In the other groves the infestation was light. They had not used any
insecticide since October and did not intend to use any, as the fungi were
getting a good start. The bloom was heavy.
LAKELAND. The grove of Geo. S. Smith was viisted on January 31, 1912.
This grove was sprayed in 1909 with fungi, at which time the whitefly was
said to have been very bad. Nothing more had been done towards controll-
ing the whitefly since. The leaves and fruit were bright. There was much
fungus in the grove (Aschersonia, Aegerita, Microcera, and the Cinnamon
Fungus) and so complete was the parasitism that it required a five-minute
search to locate a single live larva.
These notes are printed as being fair illustrations of the
work of fungi in controlling whitefly in different groves. In
some they were keeping the whitefly down in a remarkable man-
ner. In others they needed to have their efforts supplemented
by some insecticide, especially during the dry season.
COMMERCIAL SPRAYING.-As indicating the amount of fun-
gus spraying done during the summer of 1911, I give here ex-
tracts from letters from two of the men doing spraying on a
commercial scale.
Mr. Frank Stirling, writing from DeLand on September
18, 1911, states:
With two, three, or four helpers, I have sprayed altogether 94,129 trees
since March, 1911, belonging to 108 different owners, located at DeLand,
Palatka, Huntington, Deleon, Lake Weir, Tangerine, Mt. Dora. Winter Park,
Orange City, and Ft. Pierce. Another man, who worked for
me two years, began spraying on his own account and did something like
fifteen thousand trees. Another of my men went to the country around
Citra and sprayed ten or fifteen thousand. .. Besides this spray-
ing I have shipped 218,800 leaves of red, brown and yellow fungus to one
hundred and five different growers who applied it themselves . .
In regard to the cold-storage brown and yellow fungus which you sent
to me, .. I applied the brown in a grove which never had any
of it, and at the present time there is a good lot of it showing, about the
same as if it had been sprayed with fresh fungus.
On June 7 Mr. Stirling wrote again:
The fungus has progressed more rapidly this season so far than any
year previous, owing, of course, to the great amount of rain. I have
sprayed this year during the months of April and May, 18,571 trees, as
against 37,803 trees during April and May of last year; the shortage
showing that so many people are taking it up and doing their own spraying.
. n. . I have already shipped 24,000 leaves. . Around
]DeLand this year the fly is more scarce than for three or four years. This
is more so in groves where the brown fungus has been applied. There are
some groves where it was almost impossible to see a fly when the first brood
was elsewhere on the wing.
As to the efficiency of the spraying, Mr. E. B. Stevens. of
Lakeland, under date of September 22, writes:
I have examined a number of the places I sprayed and find all kinds of
variation from almost stamping out the fly apparently on one spraying, to
only a little fungus showing. The grove I sprayed three times shows the
most fungus, and seems ready to clean up this season.
Mr. Stevens, during, 1911, sprayed 39,444 trees; 3330 of
these he resprayed and 935 were sprayed a third time.
Florida Agricultural Experiment Station
IMPORTATION OF PARASITES
During July, August and September, 1911, E. W. Berger
received from the island of St. Vincent, B. W. I., several pack-
ages containing specimens of the Cocoanut Whitefly (Alcurodes
cocois), which were heavily parasitized by a chalcid enemy. It
was hoped that the latter might be induced to attack A. citri.
In all but one of the shipments the material was dead upon
arrival. The one living lot was liberated by Dr. Berger under
a tented tree. The material of the other shipments was also
placed under a tented tree, in hopes that there might a few para-
sites emerge. The t'nts were left standing all winter, but
no signs of the parasites attacking A. citri were observed. In
this work the department is indebted to Mr. J. B. Howard for
the use of the trees.
THERMAL DEATHPOINT AND OPTIMUM TEMPERATURE OF ALEU-
RODES CITRI
Some successful experiments conducted by the Kansas and
Ohio stations in freeing flour mills of insect pests by means of
beat suggested the possibility of applying the method to citrus
insects, especially the whitefly. In this connection some experi-
ments were conducted to determine the thermal death-point of
whitefly larvae and of citrus leaves and twigs. It was found
that the larvae were all killed when twigs with leaves infested
with them were immersed for ten minutes in water over 118
degrees F. The most tender leaves and twigs themselves were
not injured until the temperature of the water was raised to 125
degrees F.
With dry heat the results were somewhat different. A dry-
ing oven was used with the holes stopped up to prevent currents
of air. A dish of water was placed in the bottom of the oven
to keep the atmosphere somewhat moist. Under these conditions
the larvae were not all killed until a temperature of 136 degrees
F. had been exceeded, while tender twigs and leaves were se-
verely scorched at that temperature.
This would indicate that the use of heat as a means of kill-
ing whitefly on citrus trees is impracticable, during the actively
growing season at least. Its practicability during the winter
months, when there is no flush of growth, remains to be investi-
gated. Old leaves stood a temperature un to 145 degrees F.
The optimum temperature of the adult whitefly was found
to be between 81.5 and 82.4 degrees F. (27.5 and 28 degrees C.).
Annual Report, 1912
SPRAYING TOMATOES FOR THRIPS
This was done at Pompano, in the field of Mr. Erwin, April
6, 1912.
CONDITION OF THE CROP.-The vines were stated to be small
and late for the date on account of much wet weather, but now
seemed to be doing well as far as growth was concerned. Their
color was good. But they were not setting the fruit well, par-
ticularly on a part of the field. There were plenty of empty
peduncles on which the fruit had failed to set. In most cases
the first three clusters (hands) had failed to set a single fruit in
this part of the field. The more recent blossoms had set a few
tomatoes, indicating that perhaps the thrips were becoming less
abundant in proportion to the number of blossoms. The ma-
jority of the blossoms looked yellow and when touched dropped
off, separating at the node, a half inch below the blossom.
CAUSE.-When these yellow blossoms were opened they
were found to be infested with numerous individuals of thrips
(Euthrips tritici). If only a few insects were present in a bloom
the damage was usually largely confined to the anthers. But if
there were a half dozen or more insects in a single blossom the
pistil and especially the stigma was usually attacked. This re-
sulted in the injured part turning black, which was followed
by a yellowing of the style and its subsequent fall, in some cases
where the blossom had barely opened. Eggs were found in the
style and in the pedicel. Counts were made of the number of
thrips in fifteen blossoms taken at random. The number ranged
from one to twenty and averaged a little over eight. They were
not as numerous in the freshly-opened blooms as in the older
ones. Blossoms from the other end of the field, where consid-
erable fruit was setting, did not show nearly as many insects.
There seems to be little room for doubt that the thrips were re-
sponsible for the dropping of the blossoms. It would seem that
three or four insects in a blossom would not do sufficient dam-
age to cause a bloom to drop, but that a half-dozen or more would
usually do so.
TREATMENT.-A strip eight rods long and six rows
wide in one corner of the field was sprayed with the solution rec-
ommended by the California station against the orange thrips.
Commercial lime-sulphur (33 degrees Baume) _5 1-3 gallons
Black-leaf 40 14 fluid ounces
Water___ 200 gallons
Florida Agricultural Experiment Station
This was applied quite thoroughly to the blossoms, and time
enough (about two seconds) given to each "hand" of blossoms
to allow many of the insects to crawl out.
RESULT.-Examination immediately after spraying re-
vealed many insects caught in drops of the spray and apparently
dying. Five hours later another examination was made of the
sprayed patch. The thrips were appreciably less numerous. Of
thirty blossoms examined, nine had no thrips at all, and the
maximum number was four. The average was 1.5. Fifteen
blossoms on adjoining unsprayed rows averaged six thrips per
blossom. This makes 78 per cent. of the thrips killed by the
spray.
INSECTS OF THE YEAR
The fall of 1911 was characterized by a severe outbreak of
the cotton-leaf caterpillar, Alabama argillacea. This outbreak
occurred all over the Southern States, and flights of the adult
moth reached as far north as New York, Massachusetts, and
even Canada. The cotton over nearly the whole cotton-growing
region was almost entirely defoliated.
The bean leaf-roller (Eudamus proteus) was abundant and
destructive during the latter part of 1911, as was also the velvet
bean caterpillar (Anticarsia gemmatilis).
The pumpkin bug or green bug (Nezara hilaris) was trouble-
some during the autumn, causing severe damage in some orange
groves.
The cottony cushion scale (Icerya purchase) was found by
the Station Entomologist in Tampa, and was sent in from Ar-
cadia, Knights, and Haines City. This is the first occurrence of
this pest outside of the St. Petersburg sub-peninsula. It seems
to be slowly spreading, but has not produced any severe outbreak.
The boll weevil (Anthonomus grandis) reached Florida in
the fall of 1911. Specimens were sent in from Escambia County,
and it is reported as occurring in Santa Rosa County by the
U. S. Bureau of Entomology.
The fall army worm (Laphygma frugiperda) was sent in
from the territory between Gadsden and Walton Counties, inclu-
sive, in April and May, where it was reported as being very seri-
ous. This was also the case in the coast counties of Alabama.
The melon worm and the pickle worm (Diaphania hyalinata
and D. nitidalis) were bad in Alachua County, and were sent
Annual Report, 1912
in from other parts of the State where they were reported to
be causing serious injury.
The corn bill-bugs (Sphenophorus) were sent in from Green-
ville, where they were reported to be doing severe injury.
Some velvet beans which failed to mature before frost were
found by John Belling, assistant botanist of the Station, to be
infested with larvae. They were turned over to this department
which was able to raise them to maturity. They were found to
be Brachytarsus variegatus. This is interesting as being the
first information on the food of the larvae of this species as far
as the author knows. Most species of Brachytarsus feed on
scale insects, although they sometimes feed on seed. They have
not been observed to attack ripe velvet beans.
The mango scale (Pulvinaria psidii), said to be one of the
worst pests of citrus in southeast Asia, which was introduced
into Florida several years ago, was sent in from Buena Vista.
Respectfully,
J. R. WATSON,
Entomologist.
lxiii
Florida Agricultural Experiment Station
REPORT OF FORMER PLANT PATHOLOGIST
P. H. Rolft, Director,
SmIR: I send herewith the report of the Plant Pathologist,
covering the portion of the fiscal year up to February, 1912.
STEM-END ROT
(Phomopsis citri)
The fungus causing Stem-End rot has been identified since
last year's report was written as a species of Phomopsis, and
has been described as Phomopsis citri (Fawcett, H. S., Phyto-
pathology, II, June, 1912). This investigation, including the
cultural, infection and control work with the fungus, has been
partially reported in Bulletin 107 of the Fla. Agr. Exp. Station.
INOCULATION INTO CITRUS TREES.-Inoculation made by
Inserting bits of the fungus into cuts in the bark of branches and
twigs and stems of young trees, showed that the fungus was
capable of inducing much gumming, and of killing more or less
tissue adjacent to the cuts. The cuts which were not inoculated
healed up without gumming in nearly every case, showing that
the cuts themselves were not the cause of the gumming or of
the killing of tissue.
As many as 34 different inoculations were made, and the
results in nearly all of them were nearly the same. Details of
the results are given in Table XXV.
The fungus was isolated from 64 different specimens rep-
resenting twenty-six different localities in ten different counties.
It was isolated from fruits, from gumming twigs and branches,
and was found present in the soil from under infected trees
(Table XXIV).
INOCULATION OF FRUIT.-On August 3, 1911, a set of inocu-
lations was made by placing the fungus on the stem end of green,
immature oranges cut from the tree. The fruits were wiped
with a cloth moistened with corrosive sublimate 1-1000. In
some cases mycelium was used for infection, and in other cases
spores were placed on the stem end. The oranges were then
wrapped as for packing, and placed in an open glass jar without
moisture at a temperature of 82 to 88 degrees F. Checks not
inoculated were wrapped, and kept under the same conditions.
The checks all remained green, but some of them shriveled in a
month.
In 22 days those infected showed the rind about the stem
lxiv
Annual Report, 1912
end brown and sunken. The remainder of the surface turned
yellow. (The checks, not inoculated, were still a deep green.)
The sunken areas were of a muddy clay color to a reddish brown,
and fairly firm. A longitudinal section showed the central core
water-soaked and brown. The exterior of the seeds was also
brown. The decay progressed most rapidly in the inner part
of the rind. The juice sacs were only attacked after all the
other tissue was discolored. The decay also progressed slowly
along the divisions between the segments, but not so rapidly as
that caused by Diplodia natalensis. The discoloration due to
Phomopsis citri was not so dark, nor was the softening so rapid,
as that due to Diplodia natalensis. (Table XXVI.)
A test was made to determine the reaction of the fungus to
varying percentages of alkali and acid. The following table
gives the results of this test. (Table XXVII.)
COMBINED INOCULATIONS.-On July 29, 1911, inoculations
were made by combining pure cultures of two or more fungi in
each cut made in the bark of orange trees in the greenhouse, to
find out what the combined effect would be, not only in producing
gumming, but in killing the tissue. These trees were about one
and a half to two inches in diameter, in pots, and were in healthy
growing condition. As this was a preliminary test, only one
tree was inoculated for each combination. The results therefore
can be taken only as suggestions for further tests.
The first inoculation was made by combining bits of my-
celium from pure cultures of Diplodia natalensis, Colletotrichum
gloeosporioides, and Cladosporium herbarum, var. citricolum. In
one week there was a copious flow of gum running down from
the wound; in two weeks gum was still running, with a killed
area of one and a half by one inch; in six weeks pycnidia of Dip-
lodia had formed; in four months the bark adjacent to the killed
area was hard, brown and glazed, much as in case of regular
scaly bark or nail-head rust infection.
The second combination was Cladosporium herbarum var.
citricolum, and Colletotrichum gloeosporioides. In one week
there was only a slight gumming, without any killing; in two
weeks only a slight gumming, with a swelling of the bark on the
edges of the wound; in four months the edges of the wound
were healing, and the bark was slightly pushed up in small areas
near the wound, as in the case of Scaly Bark.
The third combination was Diplodia natalensis and Clado-
sporium herbarum var. citricolum. In one week the gum was
a r-5
Florida Agricultural Experiment Station
oozing out in great quantities; in two weeks there was a killed
area one and a half by one inch; and after four months, the gum
was still forming in large quantities.
The fourth combination was Diplodia nataleneis and Colleto-
totrichum gloeosporioides. In one week there was much gum-
ming and killing of tissue over an area of one by one and a half
inches; in two weeks the gumming was more copious; in three
weeks the tree was rapidly dying and still gumming; in four
months the tree was dead clear to the roots.
The fifth combination was Phomopsis citri and Cladosporium
herbarum var. citricolum. In one week there was a slight gum-
ming, but no apparent killing of the tissue; in two weeks there
was a small collection of gum just below the cut, and a slight
killing of the tissue; in three weeks gum was running down the
trunk, and an area of one and a half by one-half inch was
killed; in four months, pycnidia had formed on the killed area.
The sixth combination was Phomopsis citri, Diplodia nata-
lensis, and Cladosporium herbarum var. citricolum. In one
week there was considerable gumming and rapid browning of
the tissue, and the bark was killed for four inches by one-half
inch; in two weeks the tree was entirely dead.
The seventh combination was Phomopsis citri and Colleto-
trichum gloeosporioides. In one week there was a very slight
gumming with killing of the tissue, one by one-half inch at the
cut; in two weeks gumming was not abundant, and the tissue on
each side of the cut was brown and swollen; in four months the
wound had healed with swelling of the bark on each side of the
cut.
Cuts made at the same time without inoculation with fungi
healed perfectly without any gumming or dying of bark.
lxvi
Annual Report, 1912 lxvii
TABLE XXIV
LOCALITIES AND SPECIMENS FROM WHICH PHOMOPSIS CITRI WAS ISOLATme
Date Locality Specimens
Nov. 9, 1909....Ormond ------------Orange fruit
Dec. 3, 1909....Bulow .........-----.....----Orange fruit
Dec. 6, 1909....Belleair ------------.. ..Grapefruit
Dec. 11, 1909--... Winter Park .....-------Orange fruit
Dec. 29, 1909----Bradentown ..---------Orange fruit
Jan. 6, 1910-.... Leesburg -----------Orange fruit
Jan. 10, 1910... (Laboratory) ------.Orange, inoculated Dec. 27, 1909
Feb. 11, 1910----. (Laboratory) ...--------Orange, inoculated Dec. 27, 1909
Feb. 23, 1910---.... (Laboratory) -------..Tangerine orange
Feb. 23, 1910--..- Hawks Park --------Orange fruit
Mar. 5, 1910.... (Laboratory) .....-------Six inoculated oranges
Apr. 25, 1910---. (Laboratory) ...-------- Inoculated orange
Aug. 15, 1910.... Bulow ....-------------..Soil from under infected tree
Aug. 18,1910---- (Laboratory) --------Inoculated tree of June 6
Sept. 3, 1910 --....Bulow .....-------------. Grapefruit
Sept. 5,1910--- (Laboratory) --------Inoculation of August 18
Sept. 12,1910.---. Ormond ------------Soil (A. W. Street grove)
Sept. 15, 1910.--...Tavares -----------Orange
Sept.' 24,1910.... Orlando ..------------. Grapefruit (thirteen localities)
Sept 24,1910... Gotha --------------Grapefruit
Sept. 24,1910.... Winter Park --------...Oranges, from three places
Oct. 5, 1910..-. Florence Villa---- .. Grapefruit
Oct. 11, 1910.. --(Hort. grounds) ..-...Inoc. twig of Kumquat, two tests
Oct. 11, 1910-..- Winter Park..----..----..Orange
Oct. 12, 1910....Weirsdale -----------Orange
Oct. 13, 1910..---Ormond ------------Twig ('A in.) gumming
Oct. 13, 1910-.... Ormond ------------1% in. below end of twig
Oct. 13, 1910---- Ormond ------------Orange, still hanging
Oct. 24, 1910 ..-- Winter Park ....--------Grapefruit
Dec. 3, 1910..- (Laboratory) ....-------- Inoculated fruit
Dec. 7, 1910.... Florence Villa ------- Grapefruit
Dec. 14, 1910--.. ulow --------------Four tangerines
Dec. 14, 1910-....-3ulow ----------- Grapefruit
Jan. 10, 1911-....-Emeralda -----------Tangerine
Jan. 10, 1911-....-Holly Hill....-------....-- Orange
Jan. 28, 1911----Altoona ------------Under gummy area on twigs
Feb. 14, 1911-...Palmetto -----------Under gummy area on twigs
Feb. 14, 1911-....-Winter Park ..----....---Under gummy area on twigs
Feb. 14, 1911....Tampa ---.......---...----Under gummy area on twigs
Feb. 14, 1911.. Bradentown -------Grapefruit
Feb. 20, 1911--... Palmetto -----------Orange
Meh. 8, 1911..- Eastlake -----------Twigs, piece cut out under gum-
ming place.
Mch. 13, 1911....Thonotosassa ----.......---Twigs
Mch. 27, 1911....Tampa -----------Orange
May 20, 1911----Bulow -------------Twigs gumming
May 27, 1911.... -(Laboratory) --------noculation of February 28
July 27, 1911--... Gainesville (market) ..Lemon
Aug. 16, 1911....-- (Laboratory) -----....--Inoculation of August 11
Aug. 16. 1911.... -Altoona ------------.. Grapefruit
Florida Agricultural Experiment Station
TABLE XXV
INOCULATION OF CITus TU WITH STEM-zND ROT
Number of
inoculations
3 orange
trees
June 7, 1910 May 30 1 orange tree
Aug. 18, 1910
3 grapefruit
trees
2 grapefruit
trees
rI I
2 grapefruit
trees
Date of
inoculation
June 6, 1910
Bark merely
scraped, not
split.
Date of Date of
11 days. One tree
on which paper
was left for 18
da ys showed
some gumming
with softening
of bark.
t months. Bark
had ruptured
and pushed up,
but gumming
had ceased.
Ixviii
Date of
culture
May 30
How
inoculated
Cut bark of tree
in greenhouse,
and put my-
celium under:
wrapped with
oiled paper.
Check; cut but
not inoculated.
Bark slit, fungus
mycelium put
under and cov-
ered with oiled
paper.
Bark slit, fungus
mycelium put
under and cov-
ered with oiled
paper:
Results
5 days. Much gum
oozing out un-
der oiled paper.
11 days. Watery
gum running
down 4 In. to
top of soiL Bark
dead over area
1 in. by % inch.
S months. Still
gumming, but
healingonedges.
Hyaline o val
spores present,
6-9 by 4-. Pyc-
nidal spores.
Months. Nogum.
mingduringthis
time. Wound
healed perfectly.
11 days. Gum-
ming consider-
ably, and con-
tinuinw for at
least 18 days.
S months. Gum-
ming ceased,
and wound heal-
ing, with dead
area 1 by % in.
Results about the
same as above.
Aug. 18, 1910 Aug. 17
Aug. 18, 1910 Aug. 13
Aug. 18
Annual Report, 1912
TABLE XXV-Continued
Date of Date of Number of
inoculation culture inoculations
Aug. 18, 1910 Aug. 13 2 grapefruit
trees
Aug. 18, 1910 Aug. 13 1 orange tree
3 inches
diam.
Sept. 6, 1910 Aug. 13 1 orange tree
% by % in.
diam.
(green-
____ house)
Sept. 6, 1910 Aug. 13 1 orange tree
Sept. 6, 1910 Aug. 13
Sept. 6, 1910 Aug. 13
Sept. 6, 1910 i Aug. 13
Sept. 27, 1910 Aug. 12
Sept. 27, 1910 Aug. 12
1 orange tree
2 orange
trees
2 orange
trees
2 orange
trees
2 orange
trees
How
inoculated Results
Checks; cut but 11 days. No gum-
not inoculated. ming.
2 months. Heal-
ing perfectly.
Slit at base, and Woundgaping;no
mycelium put gumming took
under bark. place even dur-
ing next two
months.
Slit bark and 3 weeks. Consid-
mycelium put erable gumming.
in, 8 in. from 6 weeks. Bad
soiL wound,but heal-
ing on sides.
Slit, and bit of S weeks. G um
decayed orange mine, but not a
fruit put in. freely as above.
6 weeks. Like
I above.
Culture placed S weeks. Very
on outside of slight gumming.
bark. 6 weeks. No gum
on outside, but
bark ruptured.
Cultures placed
on outside of
green smooth
bark of small
1 yr. old trees.
Checks; cut but
no fungus put
in.
Sli t, mycelium
put in.
Checks.
No infection in 6
weeks.
3 weeks. Cuts per-
fectly healed, ano
gumming.
4 weeks. Collee-
tion of watery
gum. Wounds
afterwardsheal-
ing up.
No gumming.
Cuts healing up
perfectly.
Florida Agricultural Experiment Station
TABLE XXV-Continued
Date of
inoculation
Feb. 23, 1911
July 28, 1911
Date of
culture
Feb. 14
July 28, 1911 July 24
Number of
inoculations
4 orange
trees
2 orange
trees
1 orange tree
3 inches
diam.
1 orange tree
How
inoculated Results
Mycellum put in. 20 days. Much
watery gum oos-
ing out and run-
ning 4 in. or
more to soil.
SO days. Abund-
ance of gum
with pycnidia
forming.
38 days. Killed
area 2 to 8 by
% in. Gum still
flowing.
After several
months the gum
ceased and killed
area did not in-
crease.
Cut, but not in- 20SO days. No gum,
oculated, as no killing of tis-
checks. sue.
80 days. No gum;
healing.
S months. Healed
perfectly with.
out gumming.
Slit bark near 7 days. No gum,
soil, andfungus but wound gap-
put in. I ing.
15 days. Gum-
ming and wound
gaping widely;
only slight kill.
ing of tissue.
45 days. Healing;
gum ceased.
15 weeks. Gum-
ming again, and
bark scaling off
as in Fla. Gum-
mosis.
Slit on % in. 7 days. Gumming.
branch, 2 ft. 15days. Stillgum-
from soil. ming. Area of
bark 1 by % in.
killed. Pycnidia
formed.
2S days. Pycnidia
well formed,and
spores oozingout
of same. Spores
hyaline o val
6-7.5 by 8,point-
ed at ends, 1-8
I guttulate.
Annual Report, 1912
Date of
inoculation
TABLE XXV
Date of Number of
culture inoculations
July 28, 1911 July 24
July 28, 1911
4 orange
trees
July 24 2 trees
V-Continued
How
Chec
cut
ocu
14
soil
Slit
and
put
inoculated Results
ks. Bark 7 days. Healing;
, but not in- no gum.
elated, 4 to 15 days. Same.
in. from 22 days. Healed
1. perfectly,scarce-
ly able to dis-
cern slit. --
cut in bark, 7 days. Consider-
mycelium able gumming
under. from slit under
paraffin paper.
Not so copious
as that from
Diplodia natat-
ensis inoculated
same time;
slight killing.
15 days. Gum
hardened. Areas
in bark and
wood 1 by %
in. killed. Pyc-
nidia forming.
28 days. Gum co-
pious, over sur-
face of killed
area, and run-
ning 4 in. be-
low cut.
6 weeks. Gum-
ming ceased to
flow, and killing
of tissue appar-
ently stopped. "
bxxi
lXii Fioridfa AgtiCu~tra2 Ewperiment Statmo
TABLE XXVI
LNOCUATION Of GUN-PIIM FRMT
Inoculated Number
Aug. 3, 1911 of fruits
Checks; not inocu-
lated, not injured. 15
Woody stem end
punctured, not in-
oculated .......---------.. 11
Rind scratched; not
inoculated -----.......-- 4
Spores placed on
stem-end without
injury --------- 8
Mycelium put on
stem-end -------- 4
Spores put on punc-
tured stem-end--- 5
Mycelium put on
punctured stem-
end ------------- 5
8peres put on
smuatched rind---_ 4
Myeelam put on
scratched ilnd--- 4
Inoculated Number
Aug. 8, 1911 of fruits
Checks; not inocu-
lated, not injured- 12
Checks; woody stem-
end punctured--.... 12
Checks; rind
scratched ----........ 12
Spores put on stem-
end ------------- 10
Spores put on punc-
tured stem-end-.. 10
Spores put on
scratched rind--- 8
8 days
all gr.
all gr.
all yel.
all gr.
8 gr; 1 SER
all gr.
3 gr; 2 yel.
all yeL
all yel.
11 days
11 gr; 1 SER
all gr.
all yeL
9 gr; 1 SER
6 gr; 8 yel;
2 SER
4 yel; 4 SER
Results after
10 days 32 day
all gr. all gr.
10gr;1SER 10gr; SER
all yel. 3 yel; 1 SER
7 gr; 1SER 3 yel; 5 SER
2 gr; 2 SER all SER
8 gr; 2 SER all SER; pye.
38 gr; 2 SER all SER; py~.
all ye. all SER
all SER all SER
Results after
16 days
11 gr; 1 SER
6 gr; 5 yel;
1 SER
all yel.
4 yel; 6 SER
6 yel; 4 SER
80 days
7 gr; 4 yel;
1 SER
6 gr; 5 yel;
1 SER
all yel.
lyel; 9 SER;
pyc.
1 yel; 9 SER
1 yel; 7 SER
gr-green; yel-yellow or yellowing; SER-showing Stem-end Rot infee-
fection; pyc.-pycnidia present.
Annual Report, 1912
TABLE XXVII
PROMOPSIS Crrai
Percentage of normal Reaction of fungus after seven days
acid or alkali Standard peptonized beef agar
3 per cent. acid Chalky white spreading growth on surface. Maxi-
mum growth.
5 per cent. acid Good growth, almost as rapid as on 3 per cent.
8 per cent. acid Very small amount of growth.
10 per cent. acid Growth extremely small in amount.
12 per cent. acid Probably no growth.
30 per cent acid No growth.
Neutral Good growth with more even margins than in 3 per
cent. acid.
1.5 alkali Finer and more delicate growth than in acid.
3 per cent. alkali Still less growth and finer than in 1.5 per cent.
5 per cent. alkali Small amount of growth, more above the surface.
THE EFFECTS OF SPRAYING
In the spring and summer of 1911 some spraying tests were
made, primarily for the purpose of finding out the effects of
sprays in controlling Stem-End rot due to Phomopsis citri. Inci-
dentally, information was obtained as to the effect on scale in-
sects and whitefly. The sprays used were Bordeaux mixture,
3-3-50; commercial lime-sulphur, 30 Baume (1 gallon to 25 gal-
lons of water); and Yothers' Formula IV (3 gallons Junior red
engine oil, and 2 gallons whale-oil soap, to 200 gallons of water).
Three localities were chosen: Daytona, Winter Park and
Orlando. One plot was sprayed at each locality in May, July
and September. Counts of the numbers of scale insects per fruit
and per leaf, and of the whitefly per leaf were made, one
about September 1, a second on November 1 and a third about
December 1. It was found that Bordeaux mixture caused an
overwhelming increase of scale insects. The use of commercial
lime-sulphur, in the first two counts, somewhat diminished the
number of scale-insects;.but later, in the third count, caused a
slight increase; while Yothers' Formula IV cut them down to
practically nothing. (See Tables XXVIII-XXX.) The evident
reason for the increase of scale-insects with the use of Bordeaux
is that Bordeaux mixture kills the fungi that are parasitic on the
insects, and thus allows them to increase. This increase was so
great as to cause much injury to the tree. In one case the leaves
fell off at the end of the season.
bxiMP
Florida Agricultural Eperiment Station
TABLE XXVIII
SCALE INSECT Pu Lw
Lime
Check Bordeaux sulphur Form. IV
Orlando, Sept. 1, 1911--------.. 25.5 262 5.3 0.4
Winter Park, Aug. 31, 1911---.... 69 153 56. 0.4
Daytona, Aug. 29, 1911-------- 65.5 112 4.5 0.65
SCALE INSECTS PER FRUIT
I
Orlando, Sept 1, 1911 -------- 22 476 6.4 0.8
Winter Park, Aug. 31, 1911---.... 32 332 2.4 7.3
Daytona, Aug. 29, 1911--------- 41 302 29.0 3.8
Two sprayings, May and July.
Average of about fifty leaves counted for each plot.
Average of ten representative fruits on each plot.
TABLE XXIX
SCALE INSECTS PERa LEAF
C Bor- Lime Yothers' Second Third
Check deaux sulphur Form.IV check check
Orlando, Oct. 26.. 11.9 226 9.0 I 0.6 12.8
Winter Park, Oct.27- 10.8 92 2.7 1.0 7.9 26
Daytona, Oct. 24.... 7.5 154 4.2 0.1
i 154
SCALE INSECTS PER FRUIT
Orlando, Oct. 26-- 11.8 1 2260 35.6 0.6
Winter Park, Oct.27-' 98.5 I 1307 1 1.9 21.6 82.7 7L6
Daytona, Oct. 24----| 47.3 4110 16.6 1
Average of fifty leaves or ten fruits from each plot.
Three spraying, May, July and September.
lxxiv
Annual Report, 1912
TABLE XXX
SCALE INSECTS PER LEAF
Bor- Lime Yothers'I Second
Check deaux sulphur Form. IV check
Orlando, Nov. 28 ---------- 12.2 232 17.9 1.5
Winter Park, Nov. 28------ 6,4 106 2.6 23.4 21.9
Daytona, Nov. 29 ---------- 6.9 245 22 0.7
SCALE INSECTS PER FRUIT
Orlando, Nov. 28 ---------- 5.7 9025 I 9.1 1.1
Winter Park, Nov. 28-- ----248.3 890 9.6 30.8
Daytona, Nov. 29------ 55.7 10600 217.6 8.6
TABLE XXXI
WHITEFLY LARVY PER LEAF
Lime
Check Bordeaux sulphur Form. IV
Orlando, September 1
Live ----------------- 0.5 3.3 0.5 0.0
Emerged -------------- 0.5 1.4 0.6 0.01
Dead ----------------- 4.8 4.6 2.7 0.2
Fungus ------------------ 1.4 0.5 0.9 0.0
Total--------------- 7.3 9.8 4.7 0.3
Winter Park
Live ---------------------- 4.1 25.1 0.2 0.2
Emerged ---------------- 6.9 47.7 5.8 0.5
Dead ------------------- 30.5 39.8 11.7 6.0
Fungus ------------------ 9.6 3.9 1.0 1.4
Total----------------- 51.1 116.5 18.7 8.1
Average of fifty leaves per plot.
TABLE XXXII
WrrIWLY LA Vr P= LMai
Lime
Check Bordeaux sulphur Form. IV
Orlando, October 26
Live --------------------- 0.6 0.08 0.6 0.0
Emerged ..........------....... 1.8 0.8 2.4 0.2
Dead ----------------- 4.3 1. 3.1 0.6
Fungus ---------- 0.9 0.0 0.2 0.04
Total------ 7.5 2.3 6.1 0.8
Winter Park, October 27
Live -------------------- 0.4 0.6 0.1 0.1
Emerged ------------ 6.8 10.2 3.2 8.0
Dead -------------------- 11.2 10.7 4.9 5.6
Fungus ------------------ 5.6 0.3 0.6 0.8
Total--------------- 24.0 21.8 8.8 8.9
Daytona, October 24
Live --------------------- 3.7 12.3 2.3 0.0
Emerged ----------------- 1.8 6.7 0.8 0.0
Dead -------------------- 1.9 6.1 3.4 0.2
Fungus ------------------ 0.0 0.0 0.0 0.0
Total---------.. ------- 7.4 26.1 6.5 0.2
Average of fifty leaves per plot.
TABLE XXXIII
WHITEFLY LARVJ PER LEA"
Check
Orlando, November 28
Live -----------------..... 0.3
Emerged ------------ 2.3
Dead ----------------...... 4.7
Fungus ----------- 0.4
Total ------------ 7.7
Winter Park, November 28-
Live ------------.....
Emerged ------------
Dead ---------.........
Fungus --------------
Total-----.......
Daytona, November 29
TLive --------
Emerged ------
Dead -------
Fungus --------------
Total------------
3.0
0.4
0.9
4.3
Bor-
deaux
0.2
1.8
1.5
0.0
3.5
Lime I Yothert'
sulphur Form. IV
Second
check
1.6 6.6 0.1 3.2 1.5
9.5 9.0 5.9 5.3 4.7
16.0 12.8 8.5 10.1 9.0
1.9 0.8 0.3 3.9 0.4
29.0 28.7 14.9 22.5 15.6
16.5
3.7
0.9
0.0
21.1
1.6
1.9
1.0
0.0
4.6
0.5
0.1
0.3
0.0
0.9
Annual Report, 1912
THE SIZE AND MATURITY OF THE FRUIT.-In this same ex-
periment it was noticed that some of the solutions had an effect
not only on the size but on the time of ripening of the fruit.
The lime-sulphur appeared to have an appreciable effect in caus-
ing the sprayed fruits to ripen sooner than those unsprayed,
and the oranges treated with Bordeaux mixture and Formula
IV appeared to keep green longer than the unsprayed fruits.
The difference in the time of coloring, at Orlando, between those
sprayed with lime-sulphur and the checks was about two weeks.
Not so much difference in time was noticed between the unsprayed
fruits and those sprayed with Bordeaux mixture or Form-
ula IV. In the test at Orlando the size of the fruit was appar-
ently diminished by the use of Yothers' Formula IV. About No-
vember 1 the estimated average ratio in volume between the
fruits on the sprayed and those on the unsprayed trees was
about 7 to 10. This same difference in size and time of ripening
was not so apparent at Winter Park, and could not be made out
with certainty at Daytona.
GUMMING
The words gummosiss" and "gum disease" have been used
rather loosely in Florida for any form of gumming that takes
place in any part of the tree. The word "foot-rot" (or mal
di gomma) is applied to a form of gumming and rotting at the
base near the junction of the trunk and roots. There are at
least two forms of gumming (and probably more) in addition
to that accompanying foot-rot in orange and grapefruit trees in
Florida. In one of these there is an oozing out of gum from
cracks in the bark from branches of all sizes, which is not neces-
sarily accompanied or followed by cracking and scaling of the
bark. In the other the gumming is always accompanied or fol-
lowed by the appearance of shaggy, ulcerated areas formed by
the bark cracking up and scaling off. In the latter form of gum-
ming new bark often forms under the old over an irregular sur-
face together with cambium and woody tissue that is slightly dis-
colored and contains gum. If the branch is cut across at this
point, there will often be found more or less extensive gum pock-
ets between the layers of wood. This is probably the form of
gumming referred to by Swingle and Webber (Bul. 8. Div. of
Veg. Path. and Physiol., p. 30) as Psorosis, and which is known
as "Scaly Bark" in California. This breaking up and scaling
off of the bark sometimes occurs when but little gum comes to
lxxvii
lxxviii Florida Agricultural Experiment Station
the surface. A scaling of the bark on larger branches similar
to this, but usually extending over the whole surface of a limb
and not confined to definite patches, occurs in connection with
Florida Scaly Bark or Nail-head Rust (Bul. 106. Fla. Exp. Sta.),
a disease which is quite different from the California Scaly Bark,
or Psorosis.
These two different forms of gumming are sometimes found
on the same tree. One factor in connection with gumming, and
the cause of some of the first forms (that are not accompanied
by breaking and scaling of the bark) is the fungus, Diplodia
natalensis (Rept. Fla. Exp. Sta. 1911, p. lxi). This fungus has
been isolated from the discolored wood at different depths under
the gumming areas at least 28 times, for specimens from 18 lo-
calities (Table XXXIV). It has been grown in the laboratory in
pure cultures, and more than 40 inoculations into citrus trees
have been made both with mycelium and with spores. In almost
every case when the bark was cut and the fungus inserted a
copious flow of gum has been produced (See Table XXXV). The
fungus has been isolated from the discolored wood of a number
of these inoculated trees. Trees cut in the same way without
inoculation have in every case healed up in a regular manner.
In the Diplodia form of gumming the inner wood is often dis-
colored and blackened for some distance along the branch beyond
any outward sign of killed bark. The fungus mycelium may
be detected within this discolored wood, and cultures can be ob-
tained from it.
Whether this fungus has anything to do with the scaling off
and breaking up of the bark in the other form of gumming is yet
doubtful. It has been isolated from these patches, from tissue
that had been killed and discolored, when much gum was flowing;
but not from very early stages, nor has this shaggy-bark form
been as yet definitely produced by inoculation with the fungus.
It has also been shown that certain other fungi when inocu-
lated into citrus trees will produce some gumming, but the writer
has found none that nearly equal Diplodia natalensis in the
amount of gum induced. In July, 1911, in order to determine
to what extent other fungi could induce gum under similar con-
ditions of inoculation to that mentioned before, the following
fungi were tried: Phomopsis citri, Colletotrichum gloeospo-
rioides, Sphaeropsis tumefaciens, Alternaria citri and Alternaria
sp., isolated from leaves, and Cladosporium herbarum, Sphaerop-
sis malorum, and Fusarium gramineum, from other sources. Of
Annual Report, 1912
these, Phomopsis citri induced gumming, which was only about
one-half as copious as that due to Diplodia; Fusarium sp. in-
duced still less; and Alternaria citri and Colletotrichum gloeo-
sporioides produced only very slight amounts of gum. None of
-the others induced any gum flow. Four unidentified species of
bacteria were also used, two that had come from dead wood in
connection with the Psorosis form of gumming, and two from
otherwise diseased tissue. None of these bacteria induced any
gumming when inserted into cuts. The inoculation of Diplodia
natalensis made at this time induced a very copious flow of gum
which collected in ridges along the bark below the point of inocu-
lation with the formation of abundant pycnidia.
Trees cut in the same way, but not inoculated, healed up as
usual, with only slight scars and no gumming. One small tree
was also burned severely with an alcohol flame. This tree with-
ered in one week, and was dead in two weeks, without gumming.
Another tree was bruised by pounding, but the wound healed
up, with a browning and deadening of the tissue at the bruise, but
without any gumming.
Several inoculations were made to find out the effect pro-
duced by fungus mycelium which had been desiccated and then
treated so to kill the fungus and yet preserve possible enzymes.
'This desiccated and treated fungus mycelium was prepared by
B. F. Floyd according to Dox's adaptation of Albert and Buck-
ner's method for an enzyme powder (Bul. 120, U. S. Dep. of Agr.,
Bureau of Animal Industry). Tests at two different dates were
made. The first was on April 24,1911. Two inoculations made
by cutting the bark and inserting desiccated mycelium not treat-
ed for enzymes, resulted as follows: In one week there was con-
siderable gumming, though not so much as in an inoculation made
at the same time with fresh fungus; in one month the bark and
wood were killed over an area of one and one-half by one-third
inch. Two other inoculations were made with the enzyme pow-
der. In one week there was no gum nor killing of the tissue;
in one month, although the wound was gaping open, it appeared
to be healing almost as well as the check. The check tree. cut
but not inoculated, healed up in a month without gumming.
Another inoculation, on March 25, was made on sour orange
trees about three or four inches in diameter on the Experiment
Station grounds. These were inoculated as already described,
one free with mycelium dried but not treated for enzymes, an-
other with enzyme powder, and another as a check was cut but
lxxix .
Florida Agricultural Experiment Station
not inoculated. Just as before, the tree inoculated with the dried
fungus gummed more or less freely, and in two months there was
a killed area of 2 by 1 1-2 inches. In the one in which the
enzyme powder had been inserted into the cut there was simply
a gaping open of the wound, but no gumming, and in two months
the wound had healed without gumming, in about the same way
as the uninoculated check.
With the idea of testing out the ability of certain chemicals
to induce gum flow in citrus trees, a preliminary test was made.
These inoculations were made on trees outside the greenhouse,
and were not done with the same care to exclude possible con-
taminations as was used in the previously-mentioned inocula-
tions.
Cuts were made into the bark of limbs 1-3 to 1-2 inch in
diameter, and small amounts of different chemicals were insert-
ed without dilution. Either a considerable amount of tissue or
entire limbs were killed. The following compounds all produced
some gumming (except carbolic acid): nitric acid, sulpburic
acid, acetic acid, citric acid, phosphoric acid, carbolic acid, cop-
per sulphate, mercuric chloride, and ammonium lactate. The
same experiment was tried on peach trees with the same re-
sults.
EXPERIMENTS FOR CONTROL.-Experiments in treating trees
for the cure of Psorosis (or California Scaly Bark) form of gum-
ming were carried out in three localities. The first experiment
was with Valencia Late and Washington Navel trees at Crescent
City, which were badly affected with large scaly areas on the
large limbs, accompanied by more or less gumming. These trees
had been budded with bud-wood from California after the freeze
of 1894-5. The disease may have been introduced from Cali-
fornia at that time. The loose bark was scraped off, leaving the
new bark that had formed underneath. In a number of trees
the diseased surface was covered with grafting wax, and others
were painted with carbolineum (1 gallon diluted with a gallon
of water to which 1 pound of whale-oil soap had been added).
Certain trees were scraped in the same way and left untreated as
checks. This was done in September, 1909. Two years after-
wards the trees treated with carbolineum were more injured than
the checks. Those treated with wax were no better than the
checks.
Another experiment was tried at Orlando in July, 1911.
Diseased areas of the same kind were treated, some after scrap-
Ixxx
Annual Report, 1912
ing off the loose bark as before, and others after cutting out
the affected bark and wood of diseased areas that had recently
formed.
In the latter case the diseased bark and wood were cut out,
getting back to apparently sound tissue, and the places were
painted over, some with carbolineum followed by liquid grafting
wax, and others by 1 part of carbolineum mixed with 2 parts
of liquid grafting wax. All of these areas so treated appeared
to be healing perfectly some months after treatment. The wax
and earbolineum mixed perfectly. This substance forms a thin
hard layer over the wood and allows the new cambium to form
under it. An experiment of the same kind with. gumming
grapefruit trees was made near Daytona, with the same good
results. In this experiment some of the places were first treat-
ed with strong Bordeaux, followed by the wax. These healed up
equally well.
TABLE XXXIV
LOCALITIES FROM WHICH DIPLODIA NATALENSIS WAS ISOLATED
Date Locality Host
Jan. 3, 1909_-Gulf Hammock-----..----Sour orange
Mar. 5, 1910..City Point.....-----------Sweet orange fruit
June 14, 1910-Eustis .....---------------
Sept. 3, 1910..Crescent City (3 places) -Branches of orange (gumming)
Sept. 13, 1910-DeLand ---------------Footrot tree
Sept. 24, 1910-Winter Park (3 places) -Sweet orange fruit
Oct. 4, 1910-..Crescent City ......---------..Branch of gumming tree
Oct. 8, 1910..-City Point.....------------Fruit
Oct. 13, 1910-.Bulow ..........----------------....Branch (1 in. diameter)
Nov. 16, 1910-Winter Park ----------.....Branch
Nov. 16, 1910-Winter Park........---------..Galls on bay tree
Dec. 7, 191Q_-Florence Villa.....----..----..Grapefruit
Dec. 14, 1910-Ormond ..............-----------Gumming twig
Jan. 19, 1911-Mims -----------------Blighted orange tree (roots and
water-sprouts)
Jan. 28, 1911-Altoona ........---------------....Under gumming area on branches
Feb. 14, 1911-Tampa ......... -------Orange fruits
Mar. 13, 1911Thonotosassa .......---------..Twigs of orange tree
June 9, 1911-_Porto Rico.........-----------Orange fruits
July 29, 1911-Porto Rico.............-----------Grapefruits
Aug.-9, 1911-.DeLand ................Grapefruits
(i. r.- 4<
Florida Agricultural Experiment Station
TABLE XXXV
DIPLODIA NATAINSIS--INOCULATIONB INTO TREE
Plants
Sour orange,
I in. diam.
Date.
Date.
1910
Sept. 27'
Sweet Sept. 27
orange,
i in. diam.
Sweet Sept. 27
orange,
b in. diam.
8weet orange Sept 27
Sour orange Sept. 27
Peach tree jSept. 27
Citrus
Citrus
Citrus
Citrus
Citrus
Citrus, i in.
in diam.
Citrus
Feb.
1911.
Feb. 18
kpr. 24
How
inoculated
2
2
2
1
62
2
2
2
1
2
(
(
I in. from soil,
cut, and bit
of fungus in-
serted.
I in. from soil,
same method.
)n large limb;
same method.
Check; not in-
oculated.
Check; not in-
oculated.
Cut, and bit of
fungus i n -
serted.
*1
Sep. 12,
1910
Sep. 12,
1910
Sep. 12,
1910
Sep. 12,
1910
rut,and spores Nov. 1,
put in. 1910
Vot cut; spores Nov. 1,
put in. 1910
,heck; not in-
oculated.
'ut, and my- Jan. 18
celium put in. 1911
"ut, but not in-
oculated.
'iycelium i n -
serted into
cut.
Spores insert.
ed in cut.
0
8 :
Citrus
Peach
Peach
Citrus
Apr. 19, Peach
1911
Apr. 19, Peach
1911
Results
1 week. Gum-
ming much.
I month. Gum
hardened i n
long ridges
down to soil.
Same as above.
Same as above.
Copious g u m-
ming.
Healed up in one
month.
Healed up in one
month.
Large mass of
thick gum at
lower edge of
wound.
zI days. Much
gum oozing out.
22 days. Much
gum. Pycnidia
present.
I weeks. Areas
11 to 3 by I in.
diam.
No infection.
Healed.
12 weeks. One
with large
amount, other
with small
amount of gum.
Healed; no gum.
1 week. Gum
running down
3 to 4 in. from
slit. Tissue dy-
ing i way
around. Abund-
ant pycnidia.
1 week. Small
drop of gum on
lower edge of
slit.
Ixxxii
,
Annual Report, 1912
TABLE XXXV-Continued
Plants Dalte How o
1911' inoculated
_________^ J_______g g ,
Citrus Apr. 24
Citrus
Citrus
Citrus
Citrus tree,
outside 3 in.
diam.
1-year-old
branch of
same tree
Apr. 24
Apr. 24
Aipr. 24
Apr. 24
kpr. 24
Mycelium
treated to kill
fungus, but!
t o preserve
enzymes.
(This wa s
prepared b y
B. F. Floyd.)
Powder put
in cut.
'ycelium des-
sicated, b u t
not treated as
above, p ut
into cut.
Mycelium
placed on ex.
terior of un-
injured bark.
Checks; cut,not
inoculated.
Mycelium i n
slit, 3 inches
from soil.
Mycelium put
in slit.
Citrus
Citrus I
Apr. 19,1 Peach
1911 I
Apr. 19,
1911
Apr. 19,
1911
Peach
Peach
I month. Tissue
killed, I by I
in. Gum run-
ning down
from cut.
8 months. Healed
over, but wood
stained within,
mycelium pres-
ent.
1 week. No gum,
no killing of
tissue.
1 month. Wound
gaping, but
healing like the
checks.
1 week. Gum-
ming consider-
ably, though
not as much as
inoculations o f
fresh fungus.
1 month. Tissue
killed 11-2 by
1-3 inch.
8 months. Heal-
ing up over
wound.
No infection. No
gum produced
in 8 months.
No infection. No
gum. Healing
perfectly.
1 week. Gum-
ming copiously.
1 month. Area
2 by 11 in.
killed, and nu-
merous p y c-
nidia formed.
I week. Copious
gumming.
2 months. Dead
area 1U in.long,
and gum over
it.
lxxxiii
Results
,
bxxxiv Florida Agricultural Experiment Station
TABLE XXXV-Continued
Data,
plants 1911 a !
P~u~f D^ d
Z
How
inoculated
IM
0g 0 a
Check; cut, not
inoculated.
Mycelium p u t Apr. 19,
in cut. 1911
1-year-old
branch of
same tree
Peach tree
limb, li in.
4iam.
Same tree,
another
branch of
same fork
Wild plum
(Prunus
ep.)
Wild plum
(Prunus
Wid) plum
(Prunus
sp.)
Wild plum
(Prunus
Will plum
6 in. diam.
Apr. 24
Apr. 24
Apr. 24
Apr. 24
Apr. 24
Apr. 241
Apr. 24
Apr. 25
1
1I
2
1
2
2
21
1
Peach
Peach
Peach
Peach
Results
Check; cut but
not inocu-
lated.
Mycelium pu t
in I cut near
base.
Checks; cut,not
inoculated.
Spores of
ungus.
Checks.
Mycelium put
in cut near
base.
Apr. 19,
1911
Dec. 21,
1910
Apr. 19,
1911
No gum. Healed
completely i n
one month.
1 week. Gum-
ming copiously,
drop I by i in.
just below cut.
Gum breaking
out 2 ft. above.
1 month. Tis-
sues killed 8 by
2 inches. Gum
mass, 1 inch in
diameter, a t
wound.
1 week. No gum.
Healing with a
slight amount
of gum.
I week. No gum.
ming.
2 weeks. Drop
of gum 8 in.
above and 1 in.
to 8 in. below,
breaking
through bark,
also at cut.
No gum. Healed
in one month.
1 week. No gum.
2 weeks. Uttle
gum in top of
slit in one, none
on the other.
i month. Killed
area, 5 by I
tol.
No gum.
1 week. No gum.
2 weeks. Gum-
ming along alit
and 2 in. below.
1 month. Strip
killed 10 by 11
inches. Gum
oozing out of
bark, 10 Inches
above inoculat-
ed cut.
Annual Report, 1912
TABLE XXXV-Contimued
Plants Date,
1911
Z
Wild plum
Apr. 25
I
Prickly ash !Apr. 24
(Xanthoxy-
lum sp.)
Prickly ash
(Xanthox-
ylum), 11
m. diam.
Prickly ash
(Xanthox-
ylum), 11
in. diam.
Prunus sero-
tina (2 in.
diam.)
Apr. 25
Apr. 25
Apr. 25
m .s
How ua e i g
inoculated *5 CS
3,
t2 W 5
Check; cut as
above; no
fungus put
in.
Mycelium p u t Apr. 19,
in cut. 1911
Cut, and my-' Apr. 19,
celium put in. 1911
Check. A cut
made on same
tree above in-
oculation.
Cut,and spores
put in.
Dec. 11,
1910
Peach
Peach
Peach
Results
1 month. Heal-
i n g without
gum.
months. Healed
with only slight
amount of gum
in wound.
2 weeks. Gum
amber copious,
oozing out at
cut andthrough
sunken bark 3
in. above cut.
1 month. Bark
killed 12 inches
above,and wood
discolored much
farther.
S months. Bark
sunken 6 in.
above and 3U
in. below. Still
gumming. Pyc-
nidia formed.
Wood under-
neath discol-
ored for 27 in.
below and 16
in. above.
1 week. Slight
amt. of light-
colored gum.
2 weeks. Gum-
ming along cut
and 13 inches
above.
6 months. Killed
16 in. above
and 9 in. below.
Pycnidia.
I week. No gum.
2 weeks. Heal-
ing. No gum.
2 months. Only
small amount
of gum at cut.
I week. Small
amount of gum.
1 month. Gum
collected in
large mass at
end, and wood
discolored in -
wards.
lxxxv
lxxxvi Florida Agrioultural Experiment Station
TABLE XXXV-Continued
Date,
Plants 1911e
Pruwus sero- Apr. 25 1
tima
Prunus sero-
tina
Cherry Lau-
rel (Prunue
carolini-
ana)
Apr. 25
Apr. 25
Cberry Lau- Apr. 25
rd (Prunus
carolini-
an)
Sweet gum, Apr. 25
1 in diam.
Sweet gum Apr. 24
Sumach
SS ch
Sumach
Apr. 24
Apr. 24
How
inoculated
;i ~i
Cut, and my- Apr. 25, Peach
I celium put in. 1911
Check; cut, not
inoculated.
On same tree
higher up.
Cut, and spores
put in.
Dec. 11,
1910
Check; cut, not
inoculated.
Mycelium put Apr 19,
in. | 19119
In.I
Cheek; cut, not!
inoculated.
Cut,and spores Dec. 21,
put in. 1910
Cut, and fun-
gus put in.
Peach
Peach
Peach
Results
I week. Small
amount of gum.
1 month. Large
mass of gum,
much like that
of peach.
I week. No gum.
1 month. Healed.
No gum.
S weeks. No gum.
1 month. Gum-
ming only in
cut.
S months. Heal-
ing without
much gum.
Entirely healed
in two months
without gum-
ming.
2 weeks. Sticky
gum exuding,
killed streak of
bark 2 inches
below, 4 inches
above.
2 months. Gum
copious, run -
ning 2 ft down
I to ground.
I Bark killed 8
I in. below and 6
I in. above cut.
I Healed in two
I months without
I gumming. I n
four months a
slight amount
of gum was ob-
served at cut
4 months. Wood
and bark killed
along one side.
Pycnid a
formed.
2 weeks. Watery
substance (not
sticky) oozing
out of cut.
Strip of bark
10 inches long
killed.
I
,
Annual Report, 1912
TABLE XXXV-Continued
P"i
Plants Date, How
Plants 0 0| 1 ]| :S Results
1911 inoculated
6 :3 0
z a5
Sumach Apr. 24
Apr. 24
Apr. 24
Apr. 25
Check.
Jut,and spores Dec. 21,
put in. 1910
Check.
Cut, and my-
celium put in.
Apr. 19,
1911
Peach
Peach
Redbud
Redbud
Hackberry
1 month. Strip
5 in. below and
4 in. above cut
killed.
2 months. Strip
of bark, 6 in.
below and 51
above, killed.
Discoloration
extending into
wood 2 to 3
inches beyond
this under
bark. Pycnidia
abundant.
Completely
healed in same
time. -
2 week..-Killing
tissue, but no
gum.
1 month. Nar-
row streak in
wood, killing
for distance of
10 in;. above
and 8 in. below.
Completely
healed.
2 weeks. Exuda-
tion of sticky
substance. Kill-
ing of tissue.
Pyenidia
formed on.edge
of cut.
1 month. Strip
killed 4 inches
above, 3 inches
below.
12 months. Strip
of bark killed
through to
check cut, 6
I in. above and
and strip of
discolored wood
extending 5 in.
above and be-
low edges of
killed bark.
Py cn idia
forme~d.
lxxxviii Florida Agricultural Experiment Station
TABLE XXXV-Cbntinuad
Mulberry, 2
In. dwaM
Mulberry, 2
Ia.diam.
(Ostryi
sp.)
Ironwood
(Ostrya
sp.)
Water oak,
I in. diam.
Water oak,
i in. diam.
Magnolia
Green ash
Holly
Haw
Bush huckle-
berry
Hickory
Date,
1911
z"-^
Apr. 25
Apr. 25
Apr. 25
Apr. 25
Apr. 25
Apr. 25
How % I
inoculated
;,i !'
Cut, and my-
celium put in
Cut, not inoc-
ulated.
Cut, and my-
celium put in.
Check; cut, not
inoculated.
Cut, and my-
celium i n -
serted.
Check; cut, not
inoculated.
Two cuts, one
inoculated,
one not.
Two cuts, one
inoculated,
one not.
Two cuts, one,
inoculated,
one not.
Two cuts, one
inoculated,
one not.
Two cuts, one
inoculated,
one not.
Two cuts, one
inoculated,
one not.
Apr. 19,
1911
Apr. 19,
1911
Apr. 19,
1911
Peach
Peach
Peach
Peach
R weeks. Watery
substance oos-
ing out at slit,
bark dyingand
pycnidia
formed.
1 month. Strip
killed 3 to 4 in.
below and 8 to
10 in. above
cut.
I months. 6 to
24 in.below and
12 to 17 in.
above.
No bleeding. No
dying of tissue.
2 weeks. Tissue
slightly killed.
No bleeding.
2 months. Same.
No bleeding. No
dying of tissue.
S weeks. Streak
31 in. killed.
No bleeding.
Months. Killed
I3 in. above and
M3 in. below.
(Completely
I healed in one
I month.
No infection.
No infection.
No infection.
No infection.
No infection.
No infection.
.
Annual Report, 1912
TABLE XXXV-Continued
Plants 1911 e,
o
2:o
Sour orange,
2 in. diam.
Sour orange,
2 in. diam.
Sour orange,
11 in. diam.
Apr. 25
Apr. 25
Apr. 25
Apr. 25
Sour orange, Apr. 25
21 in. diam.
Citrus, I in.
disam
(green-
house).
Citrus, I in.
diam.
(green-
house).
Citrus, in.
diam.
(green-
house).
Citrus (out-
side).
Citrus
(green-
house)
July
July
July
July 28
How
inoculated
0 0
Cs 0 C,
9Z M
Cut, and my- Apr. 19,
celium put in. 1911
Check; cut, not
inoculated. I
Dessicated fun-
gus put in.
Enzyme pow-
der ( pre -
pared after
Dox's meth-
od).
Mycelium
serted.
Mycelium
serted.
Check; cut, not
inoculated.
Apr. 24,
1911
Apr. 24,
1911
Cut, and my- May 24,
celium put in. 1911
2 cuts,
apart.
15 in.
July 24,
1911
Peach
Citrus
(Citrus
Citrus
Peach
Peach
Citrus
Results
2 weeks. Gum-
ming copiously.
1 month. Strip
of tissue 5 by
1I in. killed.
2 months. Gum-
ming ceased.
Healing.
2 months. Com-
pletely healed
without gum-
ming.
2 weeks. Small
amt. of watery
gum at lower
edge of cut.
2 months. Area
2 by I in. killed.
Wood healing
on edges.
2 weeks. Wound
gaping more
than check cut,
but not gum-
ming.
Months. Healed
without gum-
ming.
11 days. Copious
gumming.
5 months. Heal-
ing up.
5 months. Heal-
ing up.
11 days. No gum.
Healing.
months. Healed
perfectly, with
only slight scar.
11 days. Copious
gumming.
2 months. Slit
healing along
edges. G u m-
ming ceased.
1 week. Gum-
ming copiously.
2 weeks. Streak
21 by i inch
killed.
lxxxix
Florida Agricultural Experiment Station
TA BE XXXV--Continued
Plants Date, I
Plants 91911 1
Citrus
(green-
house)
Citrus
(green-
house)
Citrus tree,
I in. diam.
Prickly ash,
I in. diam.
Prickly ash,
I in. diam.
Sumach
July 281 2
July 28
July 28
Aug. 10
Aug. 10
Aug. 10
How
inoculated
Check; cut, not
inoculated.
Bark pounded,
not inocu-
lated.
Bark burned
severely a t
points 3 in.
and 18 in.1
from base.
Cut, and fun- July 24,
gus put in. 1911
Check.
Cut, and fun-
gus put in.
a.4J
C,2U
Citrus
Results
S weeks. Beads
of gum exud.
ing 31 in. above
cut. Wood killed
between 2 cuts.
Pycnidia
abundant o n
surface under
gum.
Healed perfect-
ly, with only
slight sca r,
without gum.
ming.
I week. Healing.
No gum.
2 weeks. Healed,
with some
brown dead tis-
sue. No gum.
1 week. Leaves
withering, area
1 in. long at
burned point
full of acervuli
of C. gloeospor-
ioides. No gum-
ming.
2 weeks. Tree
dead back to 13
in. from base.
Cut off, 4 in.
from base. The
base and roots
soon died. No
gumming a t
any time.
1 week. Clear
gum oozed out
of cut.
1 month. Sunken
area It by I in.
Healed perfect-
ly in 1 month.
I week. Bleed-
ing at cut.
I month. Dead
area 1 by I in.
4 months. Pyc-
nidia and
spores about
dead area. Dis-
colored wood in
Annual Report, 1912
TABLE XXXV-Cmntinued
Plants Date.
o
Sumach
Mulberry
Mulberry
Water oak
Citrus
Citrus
Peach
Peach
Aug. 10
Sept. 20
Sept. 20
ISept. 20
Sept. 20
'0 I
nuw
How g g S
inoculated j
cd 7 3
9: C0 t)~
Checks.
Cut, and fun- July 24,
gus put in. 1911
Cheeks.
Cut, and fun-
gus put in. I
Cut, slit,
fungus
in.
and July 9,
put 1911
Checks; cut, not
inoculated.
Checks; not in-i
oculated.
Cut, and fun- July 9,
gus inoculat- 1911
ed.
Citrus
Results
one tree 4 in.
above point of
inoculation, ex-
tending to cen-
ter.
Healed perfect-
ly without
bleeding.
I week. No no-
ticeable infec-
tion.
I month. Same.
( months. Bark
cracked a n d
blackened 7 in.
above inocula-
tion.
Healed perfect-
ly.
1 week. No no-
ticeable effect.
4 months. Killed
in streaks, 3, 6
and 12 in. long.
1 week. Copious
gumming.
S weeks. Killed
1-3 by 1 to
1 1-2 in. Pyc-
nidia formed.
N o gumming.
Healed in 3
weeks.
i week. No gum.
Healing.
S weeks. N o
gum. Healed.
1 week. Gum-
ming copiously
1 in. to 3 in.
I above, and 1 in.
I below cuts.
13 weeks. Large
drops of gum,
largest I ih. in
I diam. Strips
I killed 31 in.
lengthways and
half-way
around trees.
Pycnidia
formed all
alone.
xcii Florida Agricultural Experiment Station
Respectfully,
H. S. FAWCBTT,
Plant Pathologist, California State
Commission of Horticulture.
Annual Report, 1912
REPORT OF PLANT PATHOLOGIST
P. H. Rolfs, Director
Sm: I submit the following report of the work in Plant
Pathology since February 20 of the present year, together with
the report of the assistant plant pathologist
LINES OF WORK
Upon assuming the duties of plant pathologist considerable
time was spent in going over the different lines of work outlined
for the department and familiarizing myself with the details of
this work, especially that part relating to citrus diseases. No
changes have been made in the plan as previously outlined, and
the work for the ensuing year will be carried on in accordance
with this plan as nearly as it will be possible to do so.
The project relating to the study and investigation of mela-
nose of citrus trees and fruits has recently been taken over
from the department of plant physiology and included in the
plan of work for this department
The conclusions drawn from B. F. Floyd's investigations of
this disease (Report Fla. Agr. Exp. Sta., 1911, p. lxxx) indi-
cate that the cause might be due to an organism rather than to
unfavorable growth conditions. The investigation now in prog-
ress has been taken up from that point of view to determine, if
possible, the specific cause of the disease.
The results and progress of the work thus far are given in
the following preliminary report.
MELANOSE
DESCRIPTION.-Melanose attacks the young leaves, stems
and fruit of citrus trees, forming minute spots that gradually
increase in size with the growth of the infected members. The
disease is peculiar to young, succulent tissue, but infection is ap-
parently confined within comparatively narrow limits, depending
upon the degree of succulency and age of the tissue. Tissue that
is too old is not attacked, or only feebly so, and very young tissue
seems to be immune.
Infection is first manifest by small point-like dots, sunken,
dark green, and watery in appearance; and if a leaf is attacked
the infected areas may be curled or distorted. Soon the centers
of these spots become brown and waxy, irregular in shape, and
show a tendency to spread. As growth continues, the center
xcii
Florida Agricultural Experiment Station
of the spots become more elevated, reddish brown in color, and
scab-like in appearance. Finally individual spots may coalesce,
forming irregular scab-like masses, several millimeters in extent,
with cracked or broken surfaces, dark brown to black; or they
may even form circular markings or parts of circles. Beside in-
dividual spots, circles, and irregular masses, infected fruits often
show a tear-stain effect somewhat similar to that produced by
the withertip fungus (Colletotrichum gloeosporioides Penz).
PRELIMINARY INVESTIGATIONS.-Investigations as to the na-
ture and cause of melanose were begun in the latter part of
March. Since no melanose-infected citrus trees occurred in the
vicinity of Gainesville, it was necessary to make several trips
to Mr. G. E. Snow's grove, at Eastlake, to collect specimens of
the disease for laboratory study and make field observations.
A microscopical study of the spots in various stages of de-
velopment on leaves, twigs and watersprouts, failed to show any
definite traces of an internal mycelium or bacterium. Occa-
sionally superficial mycelia or isolated spores were found asso-
ciated with some of the older spots; but they were apparently
saprophytic or accidental forms, and bore no direct relation to
the spots themselves. An examination of a number of stained
microtome sections of spots and surrounding tissues also failed
to bring out any distinct traces of internal mycelium definitely
connected with the spots. Numerous attempts to isolate an or-
ganism causing the spots, from infected leaves, fruit and twigs,
through the use of culture media, proved unsuccessful. Cultures
were made under aseptic conditions, in standard peptone agar,
prune juice, and standard bouillon. In nearly every case Collet-
otrichum appeared in the cultures after 24 to 48 hours' incuba-
tion. No account was taken of this fungus as a cause of the
spots, since its manifestations are so different from those of
melanose, and it is so prevalent in nearly every locality that its
presence was regarded as secondary. Colletotrichum very soon
over-ran the cultures, and shut out the possibility of separating
any other fungi that might have been present
INFECTION EXPERIMENTS.-Melanose has been associated to
some extent with dead wood in the trees (B. F. Floyd, Fla. Agr.
Exp. Sta. Report 1911, p. lxxx). The writer has noticed that
infected trees with any quantity of dead twigs or branches,
always showed more spottings or markings on the leaves and
young twigs immediately beneath this dead wood. This led to
a series of infection experiments with the following results.
xciv
Annual Report, 1912
Dead twigs, infected leaves, and badly infected growing
water-sprouts were collected. Washings were made from each
of these by soaking in sterile water for three to four hours. The
separate washings were then sprayed with an atomizer on young
succulent growth of the sweet orange. The treated trees were
located in the novelty orchard of the Experiment Station, and
no attempt was made to control moisture conditions. No infec-
tion resulted from any of these washings.
Another series of experiments was tried in the greenhouse
in order to control the moisture conditions. Small orange trees
in pots were used. The tops were cut back, and new succulent
growth appeared at the end of three or four weeks. A tree was
selected with four young shoots. Over one of these was sus-
pended a small bundle of dead twigs taken from a badly infected
orange tree. Over a second a small bundle of badly spotted
grapefruit leaves. Over a third a bundle of wood from an infect-
ed water-sprout. The fourth shoot was left as a check. Sterile
water from an atomizer was sprayed on the different bundles at
short intervals, and allowed to drop down on the respective shoots
for a period of an hour. The entire tree was then covered with
a large bell-jar. This was removed at the end of 36 hours. A
second tree was treated at the same time in a similar manner,
using the same bundles as in the first. This tree was left un-
covered. At the end of five days infection was produced on the
tree under the bell-jar. The young shoot that had received
the drippings from the bundle of dead wood showed a character-
istic melanose spotting on leaves and stem. The other two treat-
ed twigs and check showed no infection. No infection was pro-
duced on the second tree treated in the same manner, but not
covered with a bell-jar.
This experiment was repeated several times, and in each
case where trees were kept under a bell-jar from 24-36 hours
after treatment infection always resulted from dead wood. No
infection, however, has yet been obtained from infected leaves
or living water-sprouts that show infected areas, but further
experiments will be necessary to determine how far this will
hold true.
Two sets of experiments were tried to induce infection from
dead twigs under field conditions. Dead twigs were tied to
young succulent shoots of the sweet orange in some young trees
on the Experiment Station grounds. The weather was warm
and dry and infection did not appear until about ten days. Only
xcv
Florida Agricultural Experiment Station
one-half produced melanose. In the next series dead twigs were
tied in the same manner, but at the beginning of a rainy period,
lasting 5 or 6 days. In this case infection appeared at the
end of three days, and all were infected. Infection was heavy
and spread to adjacent leaves and twigs.
In all these cases, where infection was induced, typical
melanose spots were produced on the leaves and twigs, and, in
some cases, also the peculiar circular markings, characteristic
of the disease as it appears under natural conditions.
When it was found infection could be produced at will from
dead wood, other experiments were tried to determine whether
the spotting was due to some toxic principle contained in the
dead wood or to an organism. Washings were made from dead
twigs by soaking them in sterile water for three to four hours.
One part of this solution was filtered through a Berkefeld filter,
a second through several thicknesses of filter paper and a third
was not filtered. Agar plate cultures were made from each of
the three solutions.
Young shoots on three small orange trees in pots were
sprayed with the differently treated washings, and covered with
bell-jars. At the end of four or five days, the tree sprayed with
unfiltered washings developed a heavy characteristic melanose
infection on most of the leaves. The tree sprayed with washings
filtered through filter paper showed a few scattered spots on one
or two leaves. The tree sprayed with washings filtered through
a Berkefeld filter showed no infection.
In the agar plate-cultures made from unfiltered washings,
numerous colonies of fungi and bacteria had developed at the
end of four or five days. In the plates inoculated from wash-
ings filtered through filter paper, numerous bacterial colonies
had developed, but rather few colonies of fungi appeared. In
plates inoculated from washings filtered through a Berkefeld
filter neither bacteria nor fungi appeared. This experiment was
repeated a second time and nearly the same results were ob-
tained. The unfiltered washings produced a decided infection
on the leaves, while no infection was produced by two filtered
washings. Agar plates inoculated from the unfiltered washings
developed both fungus and bacterial colonies, while plates inocu-
lated from the two filtered washings developed only bacterial
colonies. In this case some of the bacterial organisms passed
through the Berkefeld filter and appeared in the agar plates.
While the two above experiments were only preliminary, and
xcvi
Annual Report, 1912
more extended experiments should be made along this same line
before definite conclusions are drawn, the results would seem
to indicate that melanose spotting is not due to any toxic prin-
ciple within the dead twigs, or to any bacterial organism, but
infection is probably due to some fungus form. Several unde-
termined fungi have been isolated from the plate cultures inocu-
lated from unfiltered washings. These are under observation
at present, and each will be tried in a series of infection experi-
ments as soon as sufficient development has been reached.
SUMMARY.-1. Melanose infection, identical with that pro-
duced naturally in the groves, has been produced on young leaves
and stems of the sweet orange from dead twigs and branches
taken from orange and grapefruit trees showing melanose infec-
tion.
2. No infection has resulted from leaves or green shoots
showing melanose spots, when used under the same conditions
as the dead wood.
3. Infection is influenced by moisture and degree of suc-
culence of tissue.
4. Melanose spotting is apparently not due to any toxic
principle in the dead wood.
5. Infection is probably due to some fungus, as yet unde-
termined.
Crraus SCAB
(Cladosporium citri Massee.)
This disease has been quite prevalent this season, and re-
ports of injury to grapefruit due to the attacks of this fungus
have been received from different localities in the State. Bulle-
tin 109, by H. S. Fawcett, now in press, gives a detailed account
of this disease and recommends methods for its treatment and
control.
IRISH POTATO DISEASE
LATE BLIGHT. (Phytophthora infestans Mont.)-A serious
outbreak of this disease was reported from the principal potato-
growing districts of the State, and the entire crop was probably
reduced by 25 to 30 per cent. The disease appeared about a
month to six weeks before the digging season, and, owing to
the weather conditions being favorable for the development of
the fungus, spread rapidly over the entire section. Spraying
a. r.-".
xcvit
Florida Agricultural Experiment Station
with Bordeaux mixture (5-5-50 formula) was recommended to
check the disease, and in cases where the spraying was done
before the fields were too badly infected, very favorable results
were obtained.
VEGETABLE DISEASES
The work on vegetable diseases has been carried on by 0.
F. Burger, Assistant Plant Pathologist, whose report follows.
Respectfully,
H. E. STEVENS,
Plant Pathologist
REPORT OF ASSISTANT PLANT PATHOLOGIST
BACTERIAL LETTUCE DISEASE.-A bacterial disease of the
lettuce did much damage to that crop in the State this last sea-
son. The loss to some men was heavy, up to even the whole crop.
This disease has been already described by H. S. Fawcett,
and its bacterial origin proved by inoculation, in the Florida
Report for 1908.
The characteristic symptoms of the disease are so well
marked that it need not be confused with any other lettuce dis-
ease. The edges of the leaves first turn brown, and later become
dried and blackened. Also the leaves become first brown spot-
ted, the spots afterwards turning black. Brown or black spots
may be found along the midrib.
When the lettuce begins to head, the disease gets into the
head, and causes what is known as Black Rot. H. S. Fawcett
(Report Fla. Agr. Exp. Sta. for 1908, pp. lxxx-lxxxvii, Fig. 2
and Plate V) describes this disease, and says: "The first ap-
pearance of the disease is shown by small, irregular, dark areas,
which occur most often at the edges of the leaves. * *
They become thin and translucent without causing any general
wilting of the plant." Many times infection has been noticed
at a torn place in the leaf, working back in the veins to the mid-
rib. The conditions which seem to favor the spread of the dis-
ease are warmth and wet weather. On account of our continued
rain last winter the crop was severely damaged. Also the
letting down of the canvas over the beds during warm nights
aided the work of this disease.
The infection does not always take place in the field,
xcviii
Annual Report, 1912
but may be transmitted from the seed-bed. One instance was
brought to my attention where the seed-bed was badly infected.
The grower was setting out these infected plants in the beds.
Some of the older seed-beds were so badly infected that there
were places in them a yard square filled with black, tangled,
decaying masses. The returns from this field did not begin to
pay for the fertilizer bill. (Compare R. Y. Winters, Fla. Agr.
Exp. Sta. Rept. 1908, p. xcviii).
The organism was isolated from a fresh specimen on agar
plates, transferred to beef bouillon for a day, then brushed on a
healthy lettuce plant by means of a camel's-hair brush. The
plant became infected with the diesase. An isolation was
made and the same organism recovered. Another inoculation
was made from this culture, thus showing again that this organ-
ism can cause the rotting of lettuce plants. (Compare Fla. Agr.
Exp. Sta. Rept. 1908, pp. lxxxiii-lxxxviii).
The colonies of this organism on regular agar are white by
reflected light and opalescent by transmitted light; they are
elevated, with margin distinct and entire. (Compare Rept.
1908, p. lxxxiii).
Agar stabs are usually fluorescent, as are also the cultures
made in beef bouillon. Good growth was obtained on the follow-
ing media. Two per cent each of the following, added to
regular agar: Glycerine, levulose, glucose, saccharose. When
the cultures became a month old they were brown. There was
no growth in Cohn's solution, but good growth was obtained in
Uschinskey's and Fermis' solutions. Litmus milk begins to
change color in four days, becoming pink. There also occurs a
separation of the whey and casein. A tube containing 10 cc. of
gelatin was liquified in ten days. Fermentation tubes were filled
with a medium made from standard beef bouillon, and for each
set two per cent. of the following were added: Glucose, levulose,
saccharose, mannite, glycerin, urea, and asparagin. There was
a growth in both the open and closed arms, but no gas was
formed.
The organism will grow in a solution containing 1.5 per
cent. of normal hydrochloric acid. There was growth in a solu-
tion containing 1.5 per cent of normal sodium hydrate. To the
standard beef bouillon there was added two per cent. of sodium
chloride, and a medium growth was made in the tubes.
Ten cubic centimeters of beef broth was put in test-tubes.
These were inoculated from fresh culture growing in beef broth.
xcix
|
RSS
HIDE
