A 280.37 
MH Sif A 2 
bx ee AMS=21), 
UNITED STATES DEPARTMENT OF AGRICULTURE 
Agricultural Marketing Service 
Marketing Research Division 
STUDIES OF DDVP FOR CONTROL OF CIGARETTE BEETLES IN TOBACCO WAREHOUSES 
By J. N. Tenhet, C. O. Bare, and D. P. Cmids, Stored-Tobacco 
Insects Laboratory, 1/ Richmond, Va.3; and W. F. Durhan, 
Communicable Disease Center, 2/ Savannah, Ga. 
SUMMARY 
Three series of tests were made to explore the usefulness of DDVP in 
controlling the cigarette beetle in tobacco warehouses. In an exploratory 
series conducted in semiclosed warehouses, all test insects in the airspaces 
between hogsheads of tobacco were killed by aerosols applied at the rate of 
4.25 grams of DDVP per 1,000 cubie feet; by emulsion sprays applied to the 
exposed floor and walls and the underside of the roof at a rate of 3.5 grams 
of DDVP per 1,000 cubic feet; and by a solution sprinkled in the aisles at a 
rate of 2.1 grams per 1,000 cubic feet. In semiclosed warehouses, the vapors 
continued to be effective, and insects introduced 2) and 48 hours after treat- 
ment were killed within 2) hours, Mortality was low in ventilated warehouses 
after 2h; hours. Deposits on slides showed poor aerosol distribution. Rats 
exposed in the treated warehouses for 7 days showed no signs of poisoning. 
In a second series, in which DDVP aerosols were used, test insects in 
the free spaces of warehouses were killed when exposed 1 hour to dosages of 
1 gram per 1,000 cubic feet or above. Adults exposed for 2) hours 1 week 
after treatment showed 3 percent mortality. Exposed eggs were not affected 
by a dosage rate of 4.25 grams, and there was no significant mortality of 
larvae or adults at various depths in the tobacco. 
In the third series, DDVP solutions were sprinkled on the aisles. At 
20-hour exposure rates, results were similar to those of the previous series. 
However, at shorter exposures, mortalities were lower. In warehouses treated 
at a 10-gram rate, no symptoms of poisoning were evident in rats and monkeys 
s is one of the field stations of the Stored-Product Insects Sec- 
tion, Biological Sciences Branch, Marketing Research Division, Agricultural 
Marketing Service, U. S. Department of Agriculture. 
2/ U. S. Public Health Service, Department of Health, Education, and 
Welfare. 
Agriculture--Washington November 1957 
