- 52 - 
At the Pec Dog Experiment Station tests against tobacco flea beetle 
were made with derris dust (l; - rotenoho) arid cube ousts (0.5 and 1.0;." rotenone). 
The difference in the percentage of reduction of living Sweeties with the 
rotononc and the non-rot onone dusts at the end of 72 hours was not sufficiently 
great to warrant the selection of any of the materials as outstanding. How- 
ever, when the number of dead beetles is considered the derris and cube of 
1 percent rotenone content yielded greater plant protection than the other 
materials. There was no significant difference between these two insecticides, 
although there was a tendency for the cube of 1 percent rotenone content to 
lose its effectiveness faster than the derris. 
The Secretary cf the United States Department of Agriculture (413) in 
his 1933 annual report wrote as follows: 
"Laboratory and field tests with organic insecticides, 
particularly derris and cube, have brought man/ modifications 
in the recommendations for the control of certain insect pests . 
It has been demonstrated that th~se insecticides which do not 
leave residues objectionable from the standpoint of human health 
can be effectively used against a number of different truck-crop 
pests, such ae certain cabba c ;e worms and the Mexican bean beetle, 
and that they ar^ effective against flea beetles destructive to 
growing tobacco. The further usefulness of these recently 
developed materials is evidenced by the determination that one 
application of sprays or dusts of d..rris or cub- is effective 
against the pea aphid over a longer period than other recommended 
materials such as pyrethrum and nicotine." 
In discussing insecticides suitable for combating the Colorado 
potato beetle at the Conference Internationalv; pour 1'Etudc de la Lutte en 
Conmun contre le Doryphoro held in erussols January 22 and 23, 1933, under 
the auspices of the Belgian Department of Agriculture (25), Fcytaud stated 
that powders containing 5 percent of cube or derris were in use for this 
purpose. 
The handelsmuseum of the Koloniaal Instituut of Amsterdam (249) in 
1936 reported that comparative tests on derris and cube demonstrate that 
derris is more toxic than cube having the same rotenone content. 
The "msconsin Agricultural Experimental Station (472) in its annual 
report for 1935-1933 reported that derris-talc dust containing 0.48 percent 
of rotenone controlled the striped cucumber beetle. Alkaline diluents 
(e.g., hydrat^d lime, pH 12.5) reduce the effectiveness of derris and timbo 
for cabbage worms, but the- more acid samples retain their effectiveness in 
storage. 
Walker ' and Anderson (452) in 1936 reported experiments for the control 
of cabbage worms which wore made in 1932-1936 inclusive. The authors conclude 
that repeated applications of derris and cubo dusts containing from 0.5 to 
0.75 percent rotenone and from two to three percent total extractives, and 
pyrothrun dusts containing from 0,3 to 0.5 percent pyrothrins have given good 
