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NORTH FLORIDA EXPERIMENT STATION
QUINCY, FLORIDA /
January 1, 1959 ; \
NFES Mimeo Rpt. 59-2 -
RECOMMENDATIONS FOR THE CONTROL OF INSECTS ON SH DE
GROWN TOBACCO FOR THE 1959 SEASON '
By William B. Tappan, Assistant Entomologist
The control of insects attacking shade grown tobacco, in the large part,
remains essentially the same as during recent years. However, the appearance of
new insect pests, the availability of safer or more effective materials, and the
development of more efficient and safer methods of control may bring about some
changes in recommendations in the future.
Diluents.--Experiments conducted with Fasco and Niagara diluents the
past six seasons have indicated that these materials are as safe and effective to
use as tobacco diluent. Their use will depend upon grower preference.
Observations in 1957 and 1958 showed that commercial insecticide formu-
lations containing any one of the three diluents caused some degree of plant injury
in the field. Recent greenhouse tests showed that either the diluents alone or in
combination with insecticides would injure the tobacco foliage. Conditions
necessary for injury were (1) wet foliage and (2) dust gun discharge nozzle held
at a distance not greater than 3.5 inches from the plant. Caution: Do not dust
plants while they are wet. and do hold dust gun so that discharge nozzle is at
least one foot from plants.
Malathion.--This material is chemically similar to parathion but is much
less toxic to humans. A 5% malathion dust gives good control of aphids under shade
conditions. Any grower who is concerned about the safety of parathion should give
malathion serious thought as a substitute aphicide.
Endrin.--This material as a 2% dust has been highly effective against
hornworms. Taste tests of cigars prepared from endrin treated wrappers have been
satisfactory in all cases where it has been used at the 2% level or below. It is
also effective on loopers and budworms (based on five seasons' work) and is reported
as being very effective on grasshoppers elsewhere. The residual effect of endrin
is comparable to DDT and TDE. Any grower who has not been getting satisfactory
results with DDT or TDE may wish to use 1% or 2% endrin as a substitute.
Endrin in combination with parathion forms a very potent insecticide
formulation. Five years' work with the combination in the Quincy area has not shown
any evidence of plant injury. There have been some reports of plant injury else-
where. Should the grower decide to use the combination insecticide (endrin plus
parathion) he should bear in mind that these two materials are highly toxic to
warm blooded animals. All precautions that appear on the label should be read
carefully and followed precisely.
Sevin.--This material as a 10% dust has been highly effective against
hornworms for the past two years. It has also shown promise against budworms and
loopers. Sevin apparently gives a high degree of initial kill of hornworm larvae,
and parallels endrin with respect to hornworm control. Taste tests of cigars
prepared from Sevin treated wrappers have shown no off-flavor. There has been no
appreciable amount of plant injury resulting from applications in the plant bed or
Mimeo Rpt. 59-2 Cont'd.
Thiodan.--This is a newly dvoloped insecticide which is much less toxic
to warm blooded animals than is either endrin or parathion. Work with the compound
for the past three years has shown it to be comparable to parathion for aphid con-
trol and endrin for budworm, hornworm, and looper control. However, thorough
coverage of the plant is essential to effective control. Plant injury tests have
been negative to date. Cigar taste tests have shown no off-flavor from thiodan
PREVENTION OF INFESTATION
A tightly covered plant bed and shade, with close-fitting gates kept
closed as much as possible, is partially effective in preventing insect infesta-
tions on shade tobacco. The location of gardens should be as far removed from
tobacco shades as possible. Green plants (cover crop, weeds, etc.) should be
turned under at least six weeks before transplanting time. Weeds should be de-
stroyed from around the outside of shades, especially for the control of grass-
hoppers. Plant beds and shades should be plowed under as soon as possible after
Aphids.-- Weekly applications at 10-20 pounds per acre of 1% parathion,
4% thiodan or 5% malathion dusts should be made beginning 3 weeks before trans-
planting whether or not aphids are observed, and should definitely be made within
one week of transplanting.
Cutworms.--Applications at 10-20 pounds per acre of 1% parathion plus 10C
DDT or 4% thiodan dust should be made if cutworm damage is noticed. A bait con-
taining 5% toxaphene or 1% chlordane applied at 4-5 pounds per 100 square yards
along walkways, margins of bed, and in open spaces where plants are missing will
also give good results. Do not apply baits directly on plants because plant damage
may result. Cutworms feed during the coolest hours of the day, night and early
morning. Therefore, best results will be obtained if baits are applied late in
Mole crickets.--Applications of 2 pounds of actual aldrin or 4 pounds of
actual chlordane per acre in the fertilizer will give control of mole crickets.
These applications should be made so as to overlap the beds for several yards or
some marginal damage will occur. If mole crickets appear after seeds have germi-
nated, a 5% toxaphene bait or 1% chlordane bait is recommended as for cutworms.
Vegetable weevils, flea beetles, slugs, and pillbugs.--Applications of
1% parathion or 10% DDT dusts will give satisfactory control of these pests. These
dusts should be applied at the rate of 1/2 to 3/4 pound per 100 square yards of bed
Aphids, budworms, cutworms, and flea beetles.--Directly following trans-
planting, a dust mixture containing 1% parathion or 5% malathion and 10% DDT should
be applied and followed by weekly applications until the end of the season. The
first application should be at the rate of 8-10 pounds per acre and gradually in-
creased to 15-20 pounds per acre as the plants increase in size. Four percent
thiodan dust at 15-20 pounds per acre per application at weekly intervals will give
excellent control and may be substituted for 1% parathion and 10% DDT if desired.
Mimeo Rpt. 59-2 Cont'd.
An application directly after transplanting will greatly reduce the possibility of
cutworm damage the first night Also see wireworm control below for more on cut-
Hornworms.--If hornworms are observed, 10% TDE (DDD, Rothane), 10% sevin,
4% thiodan, or either 1% or 2% endrin dusts should be substituted for DDT in the
regular weekly dust application.
Loopers.--Five years' data indicate that 1 % or 2% endrin dusts at 15 to
20 pounds per acre will give good control. Four percent thiodan has shown
excellent results for two years at 15-20 pounds per acre on a weekly schedule.
Grasshoppers.--If grasshoppers occur, 11% or 2% endrin dusts may be sub-
stituted for DDT or TDE in the regular weekly dusting program.
Wireworms.--Plant damage from transplanting water treatments has made the
method optional. Should the grower desire to continue using the transplanting
water method, he must do so at his own risk. Apply 4 ounces of 50% chlordane wet-
table powder or 4 ounces of 50% chlordane emulsion or 2 ounces of 72% chlordane
emulsion per 50 gallons of transplanting water, or apply 4 ounces of 25% aldrin
wettable powder or 4 ounces of 25% aldrin emulsion per 50 gallons of transplanting
water. Apply transplanting water containing insecticide at the rate of 400 gallons
per acre or 8, 50 gallon barrels per acre. Higher rates of application may result
in serious injury to the plants. If more water is desire, decrease the insecticide
proportionally. For example, if 800 gallons of water per acre is desired, cut the
amount of insecticide in half. Where transplanting water containing insecticide is
not used, it is recommended that 4-6 pounds of actual chlordane or 2-3 pounds of
actual aldrin be applied per acre (40-60 pounds of 10% chlordane or 40-60 pounds of
5% aldrin dusts per acre) with a dust gun to the soil surface 2-3 weeks before
transplanting and immediately plowed in. It will not be necessary to treat for
wireworms if the shade has been broadcast fumigated for the season's crop.
The latter method will adjust very well to cutworm control provided 6-8
pounds actual chlordane (60-80 pounds 10% chlordane dust per acre) are applied as
Mole crickets.--Four to six pounds of actual chlordane or 2-3 pounds of
actual aldrin per acre should give effective control of mole crickets if applied
2-3 weeks before transplanting. If mole crickets become a problem after transplant-
ing, 5% chlordane or 2J% aldrin dust may be used at the rate of 10-15 pounds per
acre. The poisoned baits mentioned for mole cricket control in seed beds are also
effective. CAUTION: These dusts and baits should not be applied directly to plants
but only in spaces between rows and plants.
WARNING: TO AVOID INJURY TO THE OPERATOR, OBSERVE MANUFACTURER'S PRECAUTIONS AS
GIVEN ON CONTAINERS OF ALL INSECTICIDES.