- 6-^ - 
Hutscn ( 211 ) in 19'^5 reported derris pre-ocr^tions to "be su-oerior 
to those of pyrethrujr. for Mexican tean "beetle control, chiefly TDecause they 
have a slight residual action, whereas there is none with the pyrethrum 
products. Derris dust? are usually made vrith some bland material such 
as talc, hentonite, chalk, tohacco dust, or flour, and contain at least 
one-half of 1 percent of rotenone. It is often possible to purchase the 
groxind derris and make up the dust by adding the diluent at home. From 25 
to 35 pounds of dust per application per acre \nll usually give good ccnti-cl. 
The Kentucky Agricultural Experi'^ent Station ( 2-6 ) in 19^5 reported 
tha.t talc was more effective as a diluent and carrier for nicotine, pyreth- 
rum, and rotenone than was fuller's earth, bentonite or trit)oli, v/hen used 
to control the Mexican bean beetle. Very absorptive clays, like fj.llcr' s 
e^^rth, were difficult to use on mornings when plants were wet with heavy 
dew, if the machine drev/ air from around the plants. 
The Maine Agricultural Expcri-ncnt St-^ticn ( 270 ) in 193^^ mention'^d 
derris as effective for the control of the Mexican bean bf^-tle when proDcrly 
used, but somewhat expensive. 
The Massachusetts A'-^Ti cultural Experiment Station ( 275 ) in 1935 
reported that rotenone sprays njid dusts gave excellent control of Mexican 
bean beetle larvae, and the sprays also gave a hi^ percentage of kill of 
adult beetles. 
The Hew Jerr.ey Agricultural Experiment Station ( 296 ) in IP35 reported 
that a comb"' nation of 16 parts of finely ground derris root containing U 
percent of rot-^none and 16 to 18 percent of total aoetone extractives, 2^ 
parts of finely ground sulfur (3OO mesh), and 59 parts of a finely ground 
clay gave practically 100-percent control of the Mexican b'-^a.n betle. 
R. J. Prentisp & Company, Inc. ( 323 ) in I935 argurd that for the 
evaluation of the insccticidal value of dusts less emphasis be placed on 
rotenone content and more on total rth:-r extractives. Dusts were prepared 
from derris containing 5 p»~rcent of rotenone and IS percent of toial ether 
extractives and also frcm another lot of derris testing 1 percent of rote- 
none and 18 percent of extractives. Dusts were made from them containing 
in each case 15 pounds of powdered derris and 85 pounds of clay. The first 
dust tested 0.75 perc< nt of rotenone and the second only 0.15 percent of 
rotenone, yet both gave substantially th*^ same s8>.isfactory results when 
Used in the field on several types of insects, including Mexican bean 
b-etler. In both cases the total active ingredients of the dust, of coiirse, 
wer-- the same, viz.; 2.70 pe'c-nt eth. r extractives. 
The South Carolina Agricultural Experiment Station (_3jf7) in I935 
reported the results of tests of rotenone dusts and spr^'ys on larvae and 
adults of Mexican bean bpctles placed on caged plants after the plants had 
been sprayed, T e derris and cube powders each contained 5 percent of 
rotenone. Results were as follows: 
UBRARY 
STATE PLANT BOARD 
