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NORTH FLORIDA EXPERIMENT STATION
January 1, 1958
NFES Mimeo Rpt. 58-1
RECOMMENDATIONS FOR THE CONTROL OF INSECTS ON SHADE
GROWN TOBACCO FOR THE 19$8 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
five 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 showed that commercial insecticide formulations con-
taining any one of the three diluents caused some degree of plant injury. It is
still too early to pinpoint the causal agent. However, investigations are being
made and definite conclusions will be forthcoming.
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 horn-
worms. 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 four 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 lN or 2% endrin as a substitute.
Endrin in combination with parathion forms a very potent insecticide formu-
lation. Four 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. Apparently plant damage was due to the stabilizer, hexamethylene tetramine,
which is used in small amounts to stabilize endrin. 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 blodded animals. All precautions that
appear on the label should be read carefully and followed precisely.
Thiodan.-This is a new experimental insecticide which is much less toxic
to warm blooded animals than is either endrin or parathion. Work with the compound
for the past two years has shown it to be comparable to parathion for aphid control
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 treated
wrappers. A small amount of the compound may be released for experimental appli-
cation to commercial shades in 1958.
Mimeo Rpt. 58-1 cont'd.
PREVEIITIOI 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 infestations 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 destroyed from around
the outside of shades, especially for the control of grasshoppers. Plant beds and
shades should be plowed under as soon as possible after harvesting.
Aphids.-Weekly applications at 10-20 pounds per acre of 1% parathion or 5%
malathion dusts should be made beginning 3 weeks before transplanting whether or:
not aphids are observed, and should definitely be made within one week of trans-
Cutworms.--Applications at 10-20 pounds per acre of 1% parathion plus 10%
DDT dust should be made if cutworm damage is noticed. A bait containing 5% toxaphent
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 hot 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 the afternoon.
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
germinated, a 5% toxaphene bait or 1% chlordane bait is recommended as for cutworms
Vegetable weevils and flea beetles.--Applications of 1% parathion or 10% DDT
dusts will give satisfactory control of these insects. These dusts should be applie'
at the rate of 1/2 to 3/4 pounds per 100 square yards of bed space.
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 fir:
application should be at the rate of 8-10 pounds per acre and gradually increased
to 15-20 pounds per acre as the plants increase in size. An application directly
after transplanting will greatly reduce the possibility of cutworm damage the first
night. Also see wireworm control below for more on cutworms.
Hornworms.--If hornworms are observed, 10% TDE (DDD, Rothane) or either 1%
or 2% endrin dusts should be substituted for DDT in the regular weekly dust applica-
Loopers.-Four years? data indicate that 1% or 2% endrin dusts at 15 to 20
pounds per acre will give good control.
Mimeo Rpt. 58-1 cont'd.
Grasshoppers.--If grasshoppers occur, 1I or 2% endrin dusts may be
substituted 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 wettable
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 resulting serious
injury to the plants. If more water is desired, decrease the insecticide propor-
tionally. 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:
5% chlordane or 2% 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
GI7EN ON CONTAINERS OF ALL INSECTICIDES.