December 1949 E-791 
STATE PL BOARD 
United States Department of Agriculture 
Agricultural Research Administration 
Bureau of Entomology and Plant Quarantine 
EXPERIMENTS WITH PYRETHRUM-OIL SPRAYS 
FOR CONTROL OF THE TOBACCO MOTH 
AND THE CIGARETTE BEETLE * 
By Joseph N. Tenhet 
Division of Truck Crop and Garden Insect Investigations 
Experiments on the control of the tobacco moth ( Ephestia elutella 
(Hbn.)) and the cigarette beetle ( Lasioderma serricorne (F.)) in stored 
tobacco were conducted in South Carolina, North Carolina, and Virginia, 
from 1941 to 1948, inclusive. The major objective was to determine 
the value of weekly applications of pyrethrum-oil sprays in preventing 
the development of damaging infestations of these insects in commercial 
warehouses of stored flue-cured tobacco. Another objective was to 
compare this method of control with more established methods. 
Experimental Procedure 
Both open and closed warehouses were included in these experi- 
ments. The tobacco moth is the more destructive pest in open houses, 
and the cigarette beetle in closed houses. 
A spray containing 0.2 percent of pyrethrins was used against the 
tobacco moth, and one containing 1 percent of pyrethrins against the 
cigarette beetle. Sprays were applied by means of a mobile power 
sprayer designed for use in tobacco warehouses (Tenhet 2). The dosage 
was 100 ml. (about 3 fl. oz.) per 1,000 cubic feet of air space. Care was 
taken to distribute the spray throughout the space in each warehouse. 
The sprays were prepared by diluting pyrethrum extract concentrates 
with a light volatile oil. The manufacturer's specifications for this oil 
were as follows: Maximum specific gravity at 60° F., 0.797; flash point 
175° F.; colorless; and no kerosene odor. 
1/ The author expresses appreciation to Q. W. Roop, of the Tobacco 
Branch, Production and Marketing Administration; to C. C. Scott, of the 
Flue-Cured Tobacco Stabilization Corporation; and to various tobacco 
companies, for their cooperation and assistance in this work. 
