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In a study of diluents with derris, preliminary results indi- 
cated the following relative rating: Talc, sulfur, pyrophyllite, 
and redwood-bark flour.— Davis (135) • 
In Connecticut, Lethane inoreased the toxicity of derris and 
cube* In dust mixtures an improper diluent may decrease the toxi- 
city of the insecticide, as do certain clays when mixed with rote- 
none-bearing materials. Ground derris root (4 percent of rotenone) 
was diluted with pyrophyllite and then tested against larvae of the 
Mexican bean beetle. The reduction in number of larvae per plant 
with a 1-percent rotenone content dust was 99.7 percent; with a 
0.5-percent dust, 99.3 percent; with a 0.25-percent dust, 98.9 per- 
cent; with a 0.125-percent dust, 88.6 percent; and with a 0.0625-per- 
cent dust, 69.9 percent.— Friend (202 , p. 210). 
In Maryland the average yields of shelled lima beans were 89.6 
pounds for a 0.75-percent rotenone dust which was effective against 
the bean beetle, and 83.5 pounds for a 0.4-percent rotenone dust 
with Lethane which gave fair control.— Graham and Ditman (240 ) . 
To prepare a spray for bean beetle control, use 3-J- pounds of 
rotenone roots (4 percent of rotenone), or 2^ pounds of rotenone 
roots (5 percent of rotenone) to 100 gallons of water. For smaller 
quantities use 1 ounce of 4-percent powder to 2 gallons of water or 
1 ounce of 5-percent powder to 2-j^ gallons. This mixture will con- 
tain approximately 0.015 percent of rotenone.— Howard and coworkers 
(294 , p. 31). 
The seeds of the yam bean (Pachyrhizus erosus Urban), used as 
a dust, killed 100 percent of first-instar larvae within 48 hours. 
An examination of 12 samples from the Western Hemisphere, using 
20 percent of ground beans in talc, showed consistently high kills 
of larvae in the laboratory.—Hansberry and Lee (2 58 ) • 
The stems and seeds of Mlllettla pachyoarpa Benth. and Pachyrhizus 
erosus Urban applied as dusts killed practically all the first-m- 
star bean beetle larvae tested.— Lee and Hansberry (360) . 
In Colorado calcium arsenate spray, rotenone dust, and 0.2 
percent pyrethrin dust gave yields not significantly different from 
that of zinc arsenite. Rotenone appeared more effective as a spray 
than as a dust. — List (367). 
A home-made rotenone dust may be prepared with derris or cube 
powder (4 percent of rotenone) 1 pound, and talc, flour, tobacco 
dust, or dusting sulfur, 7 pounds. — Maxwell (407) . 
