:' '.he tn ts 
adult insects in suction light 
in each warehouse. The first application was usua 
made as catch showed 10 or more insects. 
App >, or (' 
6 or 8 days. After the first treatment trap catches were kept below 50 
insects if . as this catch is consider* ntially dangerous 
All the spraying was done under the general supervision of the author. 
Sor: the warehouses were left untreated as checks. Others were 
dusted weekly with pyrethrum or fumigated from one to three tin* 
during the season with hydrogen cyanide, as described by Reed and 
Vinzant {I). 
Control of Tobacco Moths 
Experiment in screened, open-type warehouses . - -In an .ment 
at Richmond, Va., in 1945, trap catches were recorded in eight untreated 
warehouses, eight that were sprayed, and eight tha - dusted weer 
on the same day to control the tobacco moth. The spray contained C 
cent of pyrethrins and the dust 0.8 percent. All the warehouses we: 
approximately the same size, each about 230,000 cubic feet. T 
in the same group and were believed to be comparable in e\ iy. 
• that there was a slightly lower initial infestation in the eight 
untreated houses. 
The results are shown in table 1. In only 4 « of the sumn. 
did the catch in the s; cd 50 moths In the dusted 
.ouses the catch exceeded 50 moths in 15 
untr ouses the weekly catch was well above 50 moth 
•k. 
Th- tying was not only mon- but also ch> 
■hit- than the dusting. 
i ent in unscreened or partly screened, open-type wan 
1946, 16 unsc: 
m the 
; o.ooo cul 
Ith that in 16 s 
in thl riment the Initial lnf< 
1 . 
I 
■ 
