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August, 1947
UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
HAROLD MOWRY, Director
GAINESVILLE, FLORIDA
Plant Beds for Flue-Cured
Tobacco
FRED CLARK, G. M. VOLK and W. E. STOKES
Fig. 1.-Effect of chemical treatment of the soil on weed control in plant
beds. Left, chemically treated; right, no chemical treatment.
Single copies free to Florida residents upon request to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA
Bulletin 435
BOARD OF CONTROL
J. Thos. Gurney, Chairman, Orlando
N. B. Jordan, Quincy
Thos. W. Bryant, Lakeland
M. L. Mershon, Miami
J. Henson Markham, Jacksonville
J. T. Diamond, Secretary, Tallahassee
EXECUTIVE STAFF
John J. Tigert, M.A., LL.D., President of the
University3
H. Harold Hume, D.Sc., Provost for Agricul-
ture
Harold Mowry, M.S.A., Director
L. O. Gratz, Ph.D., Asst. Dir., Research
W. M. Fifield, M.S., Asst. Dir., Admin.
J. Francis Cooper, M.S.A., Editors
Clyde Beale, A.B.J., Associate Editors
Jefferson Thomas, Assistant Editor3
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Managers
K. H. Graham, LL.D., Business Managers
Claranelle Alderman, Accountants
MAIN STATION, GAINESVILLE
AGRONOMY
W. E. Stokes, M.S., Agronomist'
Fred H. Hull, Ph.D., Agronomist
G. E. Ritchey, M.S., Agronomists
G. B. Killinger, Ph.D., Agronomist
H. C. Harris, Ph.D., Agronomist
W. A. Carver, Ph.D., Associate
Fred A. Clark, B.S., Assistant
ANIMAL INDUSTRY
A. L. Shealy, D.V.M., An. Industrialist1
R. B. Becker, Ph.D., Dairy Husbandmans
E. L. Fouts, Ph.D., Dairy Technologist'
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M., Veterinarian'
L E. Swanson, D.V.M., Parasitologist
N. R. Mehrhof, M.Agr., Poultry Husb.'
G. K. Davis, Ph.D., Animal Nutritionist
R. S. Glasscock, Ph.D., An. Husbandman
P T. Di-: Arnold, M.S.A., Asst. Dairy Husb.'
C. L. Comar, Ph.D., Asso. Biochemist
L. E. Mull, M.S., Asst. in Dairy Tech.s
Katherine Boney, B.S., Asst. Chem.
J. C. Driggers, B.S.A., Asst. Poultry Hush.
Glenn Van Ness, D.V.M., Asso. Poultry
Pathologist
S. John Folks, B.S.A., Asst. An. Husb.
W. A. Krienke, M.S., Asso. in Dairy Mfs.
ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agri. Economist' 5
Zach Savage, M.S.A., Associate'
A. H. Spurlock, M.S.A.. Associate
ID. E. Alleger, M.S., Associate
D. L. Brooke, M.S.A., Associate
Orlando, Florida (Cooperative USDA)
G. Norman Rose, B.S., Asso. Agr. Economist
J. C. Townsend, Jr., B.S.A., Agr. Statistician2
J. B. Owens, B.S.A., Agr. Statisticians
W. S. Rowan, M.S., Asst. Agr. Statistician2
ECONOMICS, HOME
Ouida D. Abbott, Ph.D., Home Econ.'
R. B. French, Ph.D.. Biochemist
ENTOMOLOGY
A. N. Tissot, Ph.D., Entomologist'
H. E. Bratley, M.S.A.. Assistant
HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist'
F. S. Jamison, Ph.D., Truck Hort.
Byron E. Janes, Ph.D., Asso. Hort.
R. A. Dennison, Ph.D., Asso. Hort.
R. K. Showalter, M.S., Asso. Hort.
R. J. Wilmot, M.S.A., Asst. Hort.
R. 1D. Dickey, M.S.A., Asst. Hort.
Victor F. Nettles, M.S.A., Asst. Hort.
F. S. Lagasse, Ph.D., Asso. Hort.2
PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist':
Phares Decker, Ph.D., Asso. Plant Path.
Erdman West, M.S., Mycologist and Botanist
Lillian E. Arnold, M.S., Asst. Botanist
SOILS
F. B. Smith, Ph.D., Microbiologist's
Gaylord M. Volk, Ph.D., Chemist
J. R. Henderson, M.S.A., Soil Technologist
J. R. Neller, Ph.D., Soils Chemist
Nathan Gammon, Jr., Ph.D., Soils Chemist
C. E. Bell, Ph.D., Associate Chemist
L. H. Rogers, Ph.D., Biochemist
R. A. Carrigan, B.S., Asso. Biochemist
H. W. Winsor, B.S.A., Assistant Chemist
Geo. D. Thornton, M.S., Asso. Microbiologist
R. E. Caldwell, M.S.A., Soil Surveyor
Wade McCall, B.S.A., Asst. Chemist
J. B. Cromartie. B.S.A., Soil Surveyor
1 Head of Department.
2In cooperation with U. S. D. A.
3 Cooperative, other divisions, U. of F
4 In Military Service.
6 On leave.
BRANCH STATIONS
NORTH FLORIDA STATION, QUINCY
J. D. Warner, M.S., Vice-Director in Charge
R. R. Kincaid, Ph.D., Plant Pathologist
W. H. Chapman, M.S., Asso. Agron.
R. C. Bond, M.S.A., Asso. Agronomist
L. G. Thompson, Ph.D., Soils Chemist
Frank S. Baker, Jr., B.S., Asst. An. Husb.
Mobile Unit, Monticello
R. W. Wallace, B.S., Associate Agronomist
Mobile Unit, Marianna
R. W. Lipscomb, M.S., Associate Agronomist
Mobile Unit, Wewahitchka
J. B. White, B.S.A., Associate Agronomist
Mobile Unit, DeFuniak Springs
R. L. Smith, M.S., Associate Agronomist
CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Vice-Director in Charge
W. L. Thompson, B.S., Entomologist
J. T. Griffiths, Ph.D., Asso. Entomologist
R. F. Suit, Ph.D., Plant Pathologist
E. P. Ducharme, M.S., Plant Pathologist6
J. E. Benedict, B.S., Asst. Horticulturist
B. R. Fudge, Ph.D., Associate Chemist
C. R. Stearns, Jr., B.S.A., Asso. Chemist
James K. Colehour, M.S., Asst. Chemist
T. W. Young, Ph.D., Asso. Horticulturist
J. W. Sites, M.S.A., Horticulturist
H. O. Sterling, B.S., Asst. Horticulturist
J. A. Grange B.S.A., Asst. Horticulturist
H. J. Reitz, M.S., Asso. Horticulturist
Francine Fisher, M.S., Asst. P1. Path.
I. W. Wander, Ph.D., Soil Chemist
A. E. Willson, B.S.A., Asso. Soil Phys.
R. W. Jones, Asst. Plant Path.
J. W. Kesterson, M.S., Asso. Chemist
C. W. Houston, Ph.D., Asso. Chemist
EVERGLADES STA., BELLE GLADE
R. V. Allison, Ph.D., Vice-Director in Charge
F. D. Stevens, B.S., Sugarcane Agron.
Thomas Bregger, Ph.D., Sugarcane
Physiologist
B. S. Clayton, B.S.C.E., Drainage Eng.2
W. T. Forsee, Jr., Ph.D., Chemist
R. W. Kidder, M.S., Asso. An. Hush.
T. C. Erwin, Assistant Chemist
Roy A. Bair, Ph.D., Agronomist
C. C. Seale, Asso. Agronomist
L. O. Payne, B.S.A., Asst. Agronomist
Russel Desrosiers, M.S., Asst. Plant Path.
N. C. Hayslip, B.S.A., Asso. Entomologist
J. C. Hoffman, M.S., Asso. Hort.
C. B. Savage, M.S.A., Asst. Hort.
Geo. Van den Berghe, B.S., Asst. Fiber Tech.
SUB-TROPICAL STA., HOMESTEAD
Geo. D. Ruehle, Ph.D., Vice-Director in
Charge
D. O. Wolfenbarger, Ph.D., Entomologist
R. W. Harkness, Ph.D., Asst. C emist
W. CENT. FLA. STA., BROO SVILLE
C. D. Gordon, Ph.D., Geneticist i Charge2
RANGE CATTLE STATION ONA
W. G. Kirk, Ph.D., Vice-Director
E. M. Hodges, Ph.D., Associate Al
D. W. Jones, B.S., Asst. Soil Ted
E. R. Felton, B.S.A., Asst. An.
CENTRAL FLORIDA STATION,
R. W. Ruprecht, Ph.D., Vice-Di
Charge
A. Alfred Foster, Ph.D., Asso.
J. W. Wilson, Sc.D., Entomologi
Ben F. Whitner, Jr., B.S.A., Asst
in Charge
ronomist
1.
[usb.
SANFORD
sector in
I. Path.
t
Hort.
WEST FLORIDA STATION, MILTON
H. W. Lundy, B.S.A., Asso. Agronomist
FIELD STATIONS
Leesburg
G. K. Parris, Ph.D., Plant Path. in Charge
Plant City
A. N. Brooks, Ph.D., Plant Pat ologist
Hastings
A. H. Eddins, Ph.D., Plant Path in Charge
E. N. McCubbin, Ph.D., Horticul urist
Monticello
S. O. Hill, B.S., Asst. Entomolo ist' '
A. M. Phillips, B.S., Asso. Ent mologist5
Bradenton
J. R. Beckenbach, Ph.D., Hortic
Charge
E. G. Kelsheimer, Ph.D., Entom
David G. Kelbert, Asso. Hortici
E. L. Spencer, Ph.D., Soils Cher
Robert 0. Magie, Ph.D., PI. Pat]
J. M. Walter, Ph.D., Plant Path
Donald S. Burgis, M.S.A., Asst. I
Lakeland
Warren O. Johnson, B.S., Meteo
1 Head of Department.
2 In cooperation with U. S.
3 Cooperative, other divisions,
4 In Military Service.
6 On leave.
Iturist in
plogist
Iturist
ist
., Glad. Inv.
[ort.
urologist2
U. of F.
CONTENTS
Page
INTRODUCTION ........................................ 5
PLANT BED LOCATION ............ .................. ..... ... ... ... 5
PREPARATION OF PLANT BEDS ......................------. ------------- 6
CONTROLLING WEEDS IN PLANT BEDS ....................-------------------..... 6
Chemical Treatment for Weed Control ..........--- ----- ------------ 6
Weed Control by Non-chemical Treatment ...----........----...---.....----..... 9
FERTILIZATION ................. ........------- ----------------------- 9
SOWING AND MANAGING TOBACCO BEDS ....................----------------.... 10
MOLE-CRICKETS IN TOBACCO BEDS ...................----- ..-.. ---------.......... 11
TOPDRESSING TOBACCO PLANT BEDS WITH EXTRA NITROGEN ................-....... 11
BLUEMOLD IN TOBACCO BEDS .-..----.......-..-- ........ --------------- 12
PDB Treatment for Bluemold Control ...............---.... .......-- ......... 12
Fermate Treatment for Bluemold Control -..............- ----- ................. 14
DAMPING-OFF IN SEEDBEDS ..--- .......................------ -- --- ------- ... 15
Plant Beds for Flue-Cured Tobacco
FRED CLARK, G. M. VOLK and W. E. STOKES
Introduction
One hundred square yards of bed under proper care will
furnish tobacco plants to set 3 to 4 acres.
During the past several years there has been a scarcity of
good plants to set the full acreage of flue-cured tobacco at the
right time. This has necessitated intermittent planting, result-
ing in uneven growth, irregular maturity and poor quality leaf.
It costs comparatively little to grow good tobacco plants, pro-
vided the beds are managed properly. Failure to produce a
stand of vigorous plants has been due in part to (1) undesirable
location of the plant bed, (2) improper preparation and fertiliza-
tion of the plant bed, (3) heavy sowing and (4) poor manage-
ment of the plant beds after sowing, especially with respect to
the control of bluemold.
Plant Bed Location
The following factors are important in plant bed location:
1. Locate the plant bed convenient to water and where it
can be watched closely. The plant bed should be located where
it will have good drainage or this drainage should be provided
by ditches to prevent flooding.
2. A plant bed extending in a north-south direction will pro-
vide maximum sunlight throughout the day. If possible, locate
the bed so that it will be protected from cold winds but avoid
shady areas.
3. Any soil suitable for growing tobacco is suitable for a plant
bed. Choose places that are relatively free of weeds or weed
seed, or employ weed control measures. If chemical weed control
is to be used, select and treat the area in early October. It
is satisfactory to use old garden spots near the home site.
Conditions vary from farm to farm and growers may find it
necessary to modify certain operations to suit their individual
situations.
Plant Beds for Flue-Cured Tobacco
FRED CLARK, G. M. VOLK and W. E. STOKES
Introduction
One hundred square yards of bed under proper care will
furnish tobacco plants to set 3 to 4 acres.
During the past several years there has been a scarcity of
good plants to set the full acreage of flue-cured tobacco at the
right time. This has necessitated intermittent planting, result-
ing in uneven growth, irregular maturity and poor quality leaf.
It costs comparatively little to grow good tobacco plants, pro-
vided the beds are managed properly. Failure to produce a
stand of vigorous plants has been due in part to (1) undesirable
location of the plant bed, (2) improper preparation and fertiliza-
tion of the plant bed, (3) heavy sowing and (4) poor manage-
ment of the plant beds after sowing, especially with respect to
the control of bluemold.
Plant Bed Location
The following factors are important in plant bed location:
1. Locate the plant bed convenient to water and where it
can be watched closely. The plant bed should be located where
it will have good drainage or this drainage should be provided
by ditches to prevent flooding.
2. A plant bed extending in a north-south direction will pro-
vide maximum sunlight throughout the day. If possible, locate
the bed so that it will be protected from cold winds but avoid
shady areas.
3. Any soil suitable for growing tobacco is suitable for a plant
bed. Choose places that are relatively free of weeds or weed
seed, or employ weed control measures. If chemical weed control
is to be used, select and treat the area in early October. It
is satisfactory to use old garden spots near the home site.
Conditions vary from farm to farm and growers may find it
necessary to modify certain operations to suit their individual
situations.
Florida Agricultural Experiment Station
Preparation of Plant Beds
Preparation of the plant bed includes the removal of all bushes,
roots and stumps, after which the soil should be plowed, disked
and hand-raked until a smooth surface is obtained. Plant beds
on which chemicals for weed control are to be used should be
prepared in late September or early October.
The plant bed side walls may be constructed of logs or boards,
which should extend from 8 to 10 inches above ground level.
All side wall joints should fit snugly to shut out cold drafts that
may injure the young plants and to hold in PDB (paradichloro-
benzene) fumes when this material is used for the control of
bluemold.
The bed should be from 6 to 9 feet wide and as long as desired.
Beds of this width are more easily weeded, watered, topdressed
and treated for bluemold without injuring the plants than are
wider ones. Provide plenty of cross wires or supports to pre-
vent the bed cover from sagging down on the plants. Disk
down all high weeds around the bed area to prevent windblown
seed from entering the bed area after treatment.
Controlling Weeds in Plant Beds
Tobacco seed germinate rather slowly and, since weeds grow
more rapidly, there is great need for weed control to prevent
choking out of tobacco plants and competition for plant nutrients.
Weeds may be controlled in plant beds by hand cultivation and
pulling, but this method is laborious and expensive.
Chemical Treatment for Weed Control.-Chemical treatment
has proven very satisfactory, inexpensive and practical for con-
trol of weeds (Fig. 2). The chemicals used are uramon and
calcium cyanamid, singly or combined.
It is recommended that the application be made between
September 23 and October 20, preferably from October 1 to
October 10 for best results.
Uramon and calcium cyanamid may be used in 3 ways: (1)
broadcast uniformly, 1 pound of uramon per square yard of bed,
(2) 1 pound of uramon per square yard and 1/ pound of calcium
cyanamid per square yard, (3) 1 pound of calcium cyanamid per
square yard. Calcium cyanamid alone or in combination should
not be used in successive years on the same bed area for weed
control on sandy soils such as used in production of flue-cured
tobacco in Florida. There is evidence that the residual alka-
Florida Agricultural Experiment Station
Preparation of Plant Beds
Preparation of the plant bed includes the removal of all bushes,
roots and stumps, after which the soil should be plowed, disked
and hand-raked until a smooth surface is obtained. Plant beds
on which chemicals for weed control are to be used should be
prepared in late September or early October.
The plant bed side walls may be constructed of logs or boards,
which should extend from 8 to 10 inches above ground level.
All side wall joints should fit snugly to shut out cold drafts that
may injure the young plants and to hold in PDB (paradichloro-
benzene) fumes when this material is used for the control of
bluemold.
The bed should be from 6 to 9 feet wide and as long as desired.
Beds of this width are more easily weeded, watered, topdressed
and treated for bluemold without injuring the plants than are
wider ones. Provide plenty of cross wires or supports to pre-
vent the bed cover from sagging down on the plants. Disk
down all high weeds around the bed area to prevent windblown
seed from entering the bed area after treatment.
Controlling Weeds in Plant Beds
Tobacco seed germinate rather slowly and, since weeds grow
more rapidly, there is great need for weed control to prevent
choking out of tobacco plants and competition for plant nutrients.
Weeds may be controlled in plant beds by hand cultivation and
pulling, but this method is laborious and expensive.
Chemical Treatment for Weed Control.-Chemical treatment
has proven very satisfactory, inexpensive and practical for con-
trol of weeds (Fig. 2). The chemicals used are uramon and
calcium cyanamid, singly or combined.
It is recommended that the application be made between
September 23 and October 20, preferably from October 1 to
October 10 for best results.
Uramon and calcium cyanamid may be used in 3 ways: (1)
broadcast uniformly, 1 pound of uramon per square yard of bed,
(2) 1 pound of uramon per square yard and 1/ pound of calcium
cyanamid per square yard, (3) 1 pound of calcium cyanamid per
square yard. Calcium cyanamid alone or in combination should
not be used in successive years on the same bed area for weed
control on sandy soils such as used in production of flue-cured
tobacco in Florida. There is evidence that the residual alka-
Plant Beds for Flue-Cured Tobacco
linity of calcium cyanamid gives rise to increase in soil pH with
subsequent undesirable effect on the breakdown of the chemical
in these soils of low buffer capacity. Figure 2 shows the effect
of various chemical treatments the first year. Figure 3 shows
the effect of repeated use of calcium cyanamid on the same
location 2 years in succession.
Plow or disk the material into the top 4 to 6 inches of soil
and re-level the soil. Uniform application and thorough mixing
in the soil are necessary for best results.
A moist soil appears to give best results from the chemical
treatment. If the soil is dry the bed should be watered before
it is treated. If the weather remains dry the bed should be
watered intermittently after a period of 6 weeks following the
treatment. The fall of 1946 was a very dry season and only
those treated beds that had been watered escaped appreciable
plant injury. There were only about 11/ inches of rainfall from
October 10 to January 1. A dry soil may not permit the chemi-
Fig. 2.-Effect of chemical treatment on weed control and of fermate
dust on bluemold control in flue-cured tobacco plant beds. 1, Treated with
1 pound calcium cyanamid plus 1/ pound uramon for weed control and
fermate dust for bluemold control. 2, Treated with 1 pound uramon plus
1/z pound calcic lime for weed control. No bluemold control-note the
crinkled leaves caused by bluemold injury. 3, Check, no treatment. 4,
Treated with 1 pound calcium cyanamid for weed control and fermate dust
for bluemold control.
8 Florida Agricultural Experiment Station
cal to break down sufficiently to prevent injury to the small
plants (Fig. 4). Do not disturb the treated area until ready to
apply the plant bed fertilizer.
Fig. 3.-Tobacco plant and weed growth following second year of
chemical treatment for weed control. Variation in size of tobacco plants
is result of strip planting at different dates between November 19 and
December 23. Chemical treatment was made on October 8, as follows:
Upper left, 1 pound uramon; center left, 1 pound calcium cyanamid; lower
left, check; upper right (4), 1 pound uramon plus 1 pound calcium cyana-
mid; center right (5), 1 pound uramon plus 1 pound calcic lime; lower
right, 1 pound calcium cyanamid. 7- ;_ /j .
a.... ..
Plant Beds for Flue-Cured Tobacco
Fig. 4.-Tobbaco plants 5 weeks old (view of lower surfaces) showing
evidence of injury following chemical treatment. This type of injury
results if proper breakdown of the chemical has not taken place by the
time of planting. Note lack of primary roots and marginal burn of leaves.
Weed Control by Non-Chemical Treatment.-Where hand
weeding is not used it has been a common practice to sterilize
the soil used for plant beds by burning wood on the area chosen
for this purpose. Where a thorough job is done, the heat created
thereby usually destroys weed seeds and certain parasitic fungi
and nematodes. A limited number of growers also have used
"steam pans" for soil sterilization, but this is a very expensive
method and equipment is not generally available.
The practice of selecting new plant bed sites which are rela-
tively free of weed seeds has been used by many growers. Areas
which have never been cultivated have proven to be the most
desirable for this practice.
Fertilization
Tobacco plants are sensitive to a high concentration of chlorine
in the fertilizer and tobacco fertilizers are generally low in
chlorine content. A 4-9-3 formula is especially recommended
for tobacco plant beds, but any good tobacco field fertilizer may
be used. Fertilizer should be broadcast and disked 2 to 3 inches
Florida Agricultural Experiment Station
into the soil. Two pounds of fertilizer per square yard are
recommended where no chemical treatment is used. If the
chemical weed control treatment has been used the fertilizer
applications may be reduced to 1 pound per square yard. Ex-
cessive use of a fertilizer may cause serious loss of young tobacco
plants.
The fertilizer should not be worked in deeper than 2 to 3 inches
so that it is available to young plants, and the soil should not be
worked as deep as the depth of the chemical treatment because
of the possibility of turning up viable weed seed.
Sowing and Managing Tobacco Beds
It is best to seed from December 20 to January 10, preferably
about January 1. This gives ample time to have plants large
enough to transplant from March 20 to April 10, which is con-
sidered the best transplanting period. One ounce of seed per
100 square yards is recommended. Mix the seed with a filler
such as dry sand, or a small amount of the bed fertilizer. This
extra material is needed to get even distribution of the seed
over the bed. It is advisable to divide the bed into small lands
and sow each separately. Do not mix the seed with corn meal,
cottonseed meal or tankage. These materials attract mole-
crickets and cutworms and in warm, moist weather may cause
a green scum to appear on the soil surface and interfere with
the growth of the young plants.
After the seeds are sown trample or roll them into the soil
surface. Have a dry top soil when seeding, as moist soil will
adhere more readily to the feet or roller and may result in un-
even stands. Light sprinkling or careful watering after seed-
ing and packing is advisable to aid in settling the soil about
the small seeds. Do not allow the top of the soil to become dry
during germination because the small seeds are located on or
near the surface and drying may kill or weaken the young seed-
lings. Throwing water from buckets tends to wash the seed
into low areas of the bed. This results in uneven stands. It
has been observed that some chemically treated soils are some-
what impervious to water. Therefore, especial care in watering
is necessary to insure good seed germination.
Tobacco plant beds should be protected in frost danger areas.
Regular cheesecloth, 22 to 28 threads per square inch, is gen-
erally used. This cover protects plants from frost and aids
in conservation of soil moisture. The cover is generally attached
Plant Beds for Flue-Cured Tobacco
to the side walls with small nails spaced closely enough to prevent
sagging. Extra protection should be provided on extremely cold
nights, particularly if the temperature drops below 260 F. for
several hours. Plants that are in the 2- to 3-leaf stage are not
as susceptible to cold injury as larger plants. Second hand to-
bacco covers, tarpaulins, pine straw, tobacco sheets and PDB
heavy covers may be used satisfactorily. Remove regular covers
when the plants are about the size of a half dollar to allow them
to dry faster and harden as they grow. Hardened plants survive
better than tender ones when transplanted to the field.
Mole-Crickets in Tobacco Beds
Frequently mole-crickets cause considerable damage in tobacco
beds by eating the plant roots and loosening the soil, causing
plants to die. Poison baits are effective in controlling these
pests. The following are recommended:
(1) 1 pound sodium fluosilicate in 1 pound paris green or cryolite in
12 pounds wheat bran OR 25 pounds wheat bran
Mix poison and bran while dry and add enough water to make
crumbly, not soupy. Apply about 2 pounds per 100 square yards
of bed.
(2) 5 pounds corn or cottonseed meal
5 pounds wheat bran or shorts
1/ pound calcium arsenate
2 quarts of molasses or syrup
Mix thoroughly and apply 2 to 4 pounds per 100 square yards.
All bait should be applied in the late afternoon, that it may
be fresh when the pests come out to feed. Mole-crickets feed
very little in dry soil or during cold nights and it is best to
apply bait immediately after a rain or watering of the bed.
The bait should be strewn around the edges of the bed, between
alleys and in places where the plants are sparse or missing.
Avoid getting bait on the plants, as injury may result. Two
or more applications on successive days are recommended. Ap-
plications of mole-cricket poisons may have to be repeated every
7 to 10 days.
Topdressing Tobacco Plant Beds with Extra Nitrogen
Tobacco plant beds that have been fertilized as recommended
will need very little nitrogen topdressing, unless heavy rains
with accompanying leaching occur. Two or 3 topdressings us-
Plant Beds for Flue-Cured Tobacco
to the side walls with small nails spaced closely enough to prevent
sagging. Extra protection should be provided on extremely cold
nights, particularly if the temperature drops below 260 F. for
several hours. Plants that are in the 2- to 3-leaf stage are not
as susceptible to cold injury as larger plants. Second hand to-
bacco covers, tarpaulins, pine straw, tobacco sheets and PDB
heavy covers may be used satisfactorily. Remove regular covers
when the plants are about the size of a half dollar to allow them
to dry faster and harden as they grow. Hardened plants survive
better than tender ones when transplanted to the field.
Mole-Crickets in Tobacco Beds
Frequently mole-crickets cause considerable damage in tobacco
beds by eating the plant roots and loosening the soil, causing
plants to die. Poison baits are effective in controlling these
pests. The following are recommended:
(1) 1 pound sodium fluosilicate in 1 pound paris green or cryolite in
12 pounds wheat bran OR 25 pounds wheat bran
Mix poison and bran while dry and add enough water to make
crumbly, not soupy. Apply about 2 pounds per 100 square yards
of bed.
(2) 5 pounds corn or cottonseed meal
5 pounds wheat bran or shorts
1/ pound calcium arsenate
2 quarts of molasses or syrup
Mix thoroughly and apply 2 to 4 pounds per 100 square yards.
All bait should be applied in the late afternoon, that it may
be fresh when the pests come out to feed. Mole-crickets feed
very little in dry soil or during cold nights and it is best to
apply bait immediately after a rain or watering of the bed.
The bait should be strewn around the edges of the bed, between
alleys and in places where the plants are sparse or missing.
Avoid getting bait on the plants, as injury may result. Two
or more applications on successive days are recommended. Ap-
plications of mole-cricket poisons may have to be repeated every
7 to 10 days.
Topdressing Tobacco Plant Beds with Extra Nitrogen
Tobacco plant beds that have been fertilized as recommended
will need very little nitrogen topdressing, unless heavy rains
with accompanying leaching occur. Two or 3 topdressings us-
Florida Agricultural Experiment Station
ually are ample under any condition. The need for topdressing
is indicated commonly by an off-color appearance of the plants.
However, a yellowing of the leaves due to disease, cold weather
or overfertilization will not be remedied by additional nitrogen.
Excessive use of nitrogen for topdressing may result in rootburn,
temporarily retarded growth and increased susceptibility to cold
damage.
Nitrate of soda is the most commonly used topdressing ma-
terial. A solution of 3 to 5 pounds in 100 gallons of water
applied to 100 square yards of bed is preferable to a dry applica-
tion of the fertilizer which must be followed by additional
irrigation.
Finely pulverized stable, poultry and sheep manure are very
satisfactory as fertilizers. These materials are best applied in
a solution obtained by immersing a bushel bag of manure for
2 or 3 days in a barrel of water. The liquid will be sufficient
for .100 square yards of bed, but additional water should be
used to prevent burning of the plants.
Bluemold in Tobacco Beds
Bluemold is the most destructive disease attacking tobacco
plant beds in Florida. There are several methods of control,
of which PDB and fermate (Fig. 2) are the most widely used
at present. PDB can be applied after the first signs of blue-
mold are noted in the bed, but fermate will give protection only
if the plants are kept covered with it and bluemold is not allowed
to get started.
There is an erroneous belief that nitrate of soda or potassium
nitrate will control bluemold. The latter materials serve only
as an aid in the recovery of bluemold-injured plants if they
survive the disease. PDB and fermate are the 2 materials
generally recommended by research workers.
PDB Treatment for Bluemold Control.1- The following steps
are necessary to control bluemold with PDB: (1) Obtain PDB
size No. 6 crystals and heavy 56-60 mesh cover well in advance
of the bluemold season. (2) Construct beds with tight side
walls and sufficient cross wires to hold the cover if PDB use
is anticipated. Watch daily for signs of bluemold. (3) Apply
PDB treatment when bluemold is observed. It is not recom-
1Controlling Tobacco Downy Mildew (Bluemold) with Paradichloroben-
zene, by W. B. Tisdale and R. R. Kincaid. Fla. Agr. Exp. Sta. Bul. 342.
1939.
Plant Beds for Flue-Cured Tobacco
mended as a preventive. Close examination of the plant beds
is advisable when bluemold is reported in the vicinity. (4) Use
2 or 3 pounds of PDB for 100 square yards, per treatment. Two
to 3 applications on successive nights are recommended for best
results. The temperature has a considerable effect on rate of
vaporization; thus for temperatures above 50 to 600 F., use
11/2 to 2 pounds per 100 square yards; for lower temperatures
the 2- to 3-pound rate is preferable. Apply in the late after-
noon. Excessive concentration of PDB vapors will burn the
plants (Fig. 5). (5) Apply the PDB crystals (size No. 6 pre-
ferred) on a 5- or 6-inch board or scatter over regular tobacco
bed cover. Do not allow covers to sag down on plants, and
be careful in applying the crystals on the board, as any crystals
falling on plants may burn them. (6) Remove heavy cover
not later than 9:00 A. M. on sunny mornings. When the tem-
perature is below 500 F., and when cloudy and foggy weather
prevails, it is possible to leave covers over the beds for a longer
time. (7) Repeat treatment as often as necessary, generally
Fig. 5.-Effect of improper use of PDB vapors in a tobacco plant bed.
Note the curled and distorted leaves.
Florida Agricultural Experiment Station
from 7- to 10-day intervals. (8) One heavy treating cover can
be made to treat 2 or 3 beds, provided they are the same size.
This reduces the cost per yard for the treatment. The covers
are very helpful on cold nights, and they are excellent to cover
tobacco that has been cured. With proper care, a cover is usable
for 4 to 5 years. The heavy covers used in bluemold treatment
should be at least 6 to 8 inches wider than the bed and fully
that much longer than the bed so as to fit down over the side
walls.
Fermate Treatment for Bluemold Control.2- Fermate 3 is a
powdered material that may be used very satisfactorily for
bluemold control as either dust or a spray.
The dust treatment requires more fermate than the spray
treatment, but it costs less to apply. Mix 112 pounds of fermate
to 81/ pounds of talc, pyrax or Fullers earth for a 157% dust.
It is not necessary to use the pure fermate. It will increase
the cost and may injure the young plants. A 15% dust will
give excellent control when correctly used.
Begin to apply the 15% dust twice a week (more often if
weather is rainy) with a rotary hand duster or blower at the
rate of about 2 pounds per 100 square yards of bed, when the
plants are about the size of a dime, or when bluemold is known
to be in the vicinity. As the plants continue to grow, increase
the quantity to 4 pounds per 100 square yards, per application,
when plants are about large enough to transplant. It is prefer-
able to dust when the plants are wet (after watering, rain or
dew) and when there is the least wind. Ten or more applications
may be necessary for a season. Continue until plants have been
transplanted.
Approximately 40 to 50 pounds of a 15% fermate dust will
be adequate for 100 square yards of plant bed per season. Two
to 3-yard width plant beds may be dusted from along the side
wall. Dusting through the cloth is permissible when the plants
are small, but the cloth should be removed before dusting after
the plants are half the size for transplanting. A uniform cover-
age of dust on the plants at all times is highly desirable for
best results.
Fermate as a Spray.2- Mix 3 ounces fermate in 61/4 gallons
water, 6 ounces fermate in 121/ gallons water, or 12 ounces
"Bluemold Control in Tobacco Beds. U. S. Dept. of Agr. AIS 37.
"Fermate: ferric dimethyl dithiocarbamate.
Plant Beds for Flue-Cured Tobacco
fermate in 25 gallons water. (7 level tablespoonfuls fermate
equal 1 ounce.)
The amount of solution to mix depends on the yardage to be
sprayed. Weigh or measure correctly the amount of fermate
to be used. Place this material in a fruit jar or other suitable
container, put on the cover and shake thoroughly until all the
powder is wet, then pour into the correct volume of water needed
for spraying. Three gallons per 100 square yards should be
used when the plants are about the size of a dime. As they
grow larger use up to 5 to 6 gallons of spray per application.
Spray at least twice a week. A pressure or small stirrup pump
is recommended. A very fine mist or spray is necessary to get
the proper leaf coverage.
Fermate is a preventive and must be used as recommended.
Thoroughness and diligence are required to get the best results.
Damping-Off in Seedbeds
This disease is not of common occurrence in tobacco beds
when managed as described in this bulletin. However, when it
does appear its progress can be checked by spraying the beds
with yellow cuprocide, wettable spergon or fermate. The use
of fermate for controlling bluemold will help materially in con-
trolling "damping-off". However, "damping-off" usually causes
greatest loss of plants soon after they emerge and before the
time to begin spraying or dusting with fermate for bluemold
control. Recommended amounts of the materials are as follows:
1. Yellow cuprocide: 5 level teaspoons for 614 gallons of
water, 1 pound per 100 gallons.
2. Wettable spergon: 4 ounces for 6 gallons of water or 3
to 4 pounds per 100 gallons of water.
3. Fermate: 11/i ounces or 7 tablespoonfuls for 61/4 gallons
of water or 11/2 pounds for 100 gallons of water.
For uniform distribution spray the solution on the bed. When
sprayed, 3 or 4 gallons per 100 square yards are sufficient.
When the plants are ready to be set in the field, avoid tramp-
ling when pulling them. It is best to water the plants before
pulling because the roots are broken more easily when pulled
from dry soil. Water the bed immediately after pulling to
settle the soil around the plants left in the beds.
ACKNOWLEDGMENTS
The writers are indebted to Dr. W. B. Tisdale and the late J. R. Watson
for assistance on disease and insect control, respectively.
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