59 
Derris dast: containing 0.6 percent rotenone (derris 
root diluted with clay). 
Derris spray: sound derris root used at a dilution of 
1:200 with SS-3 spreader at a dilution of 
1:1600. 
P.otenone spray: a commercial product of cube root, con- 
taining 2.5 percent rotenone, used at a 
dilution of 1:200. 
Calcium arsenate: 1 part diluted with 9 parts of gypsum. 
Pyre thrum dust: a concentrated pyre thrum dust containing 2 
percent pyrethrins diluted with talc 1:9. 
Beetles were also caged over untreated plants to serve as a check. 
Twenty-four hours after the insecticides were applied, counts were 
made to determine the hilling powers of the dusts and sprays. The 
results obtained are as follows: 
Number 
Number 
of 
Number 
Percent 
Treatment 
of 
tests 
bectl 
3S 
killed 
killed 
Derris dust 
4 
70 
70 
100.0 
Derris spray 
3 
47 
46 
97.9 
Commercial rotenone 
spray 
r-7 
o 
58 
39 
67.2 
(derived from cube 
) 
Calcium arsenate 
2 
40 
18 
45.0 
Pyre thrum dust 
38 
38 
100.0 
Check 
4 
87 
1 
1.1 
Derris was also the most effective insecticide when "beetles were 
introduced into the cages 5 days after spraying or dusting. 
In a block of Hubbard squash, one-half of the plants were 
treated v/ith derris dust and one-half with cube dart, also containing 
0.6 percent rotenone. There was no perceptible difference between the 
two, as the killing action was immediate in both cases. 
Prom these tests it may be concluded that derris dust, con- 
taining 0.6 percent rotenone, is the most effective treatment against 
the striped cucumber beetle and is to be preferred to the calcium 
arsenate, which heretofore has been the standard recommendation of 
this Station. 
Batchcldcr et al. (22) in 1937 reported good control of the 
European corn borer, Pyrausta nubile! is Hbn. , in Connecticut with 
derris spray, but derris dust was unsatisfactory. As a spray finely 
powdered derris (rotenone 4 percent) was used at the rate of 4 pounds 
per 100 gallons of water. In dust form 1 part derris to 8 parts of 
talc wore- used to obtain approximately 0.4 percent rotenone content. 
