-63- 
Calcium arsenate-sulfur mixtures, with derris added, effec- 
tively controlled the cotton aphid and boll weevil. Treatments 
of calcium arsenate plus nicotine, the arsenete-sulfur mixture plus 
nicotine, and Lethane 60, all gave significantly better aphid 
control than calcium arsenate plus 0.5 percent of rotenone. — licGarr 
(381); MoGarr and Henry (382 ). 
Serious infestations of the cotton aphid may be prevented by 
using a mixture of calcium arsenate and derris or cube so that the 
finished product contains 0.5 percent of rotenone.— Little and 
Martin (368 , p. 108). 
Dusts made by nixing 20 pounds of derris or cube (5 percent of 
rotenone) with 80 pounds of calcium arsenate have been used on 
cotton plants to prevent the increase of aphids that often follows 
dusting with calcium arsenate. Since commercial calcium arsenate 
may contain up to 10 percent of free hydrated lime, and since the 
insecticidal value of the derris or cube is destroyed in an alkaline 
environment, such mixtures should not be used after they have stood 
several months. It is estimated that 50,000 pounds of derris and 
cube were used in 1941 for dusting cotton.-- Roark (505 ). 
The effect of insecticidal drift in small plots was tested 
upon the cotton aphid. The number of aphids found in each plot after 
the treatments started averaged 12.5 per square inch in the four 
check plots, 22.7 in the two plots dusted with standard calcium 
arsenate, 7.6 in the two plots dusted with a mixture of this arse- 
nate and derris, and 25.8 in two plots dusted with a special cal- 
cium arsenate.--Saith and coworkers (551 ) . 
Calcium arsenate and derris, cube, or tirbo mixtures were equally 
effective against the cotton aphid, and gave highly significant de- 
creases in aphid infestation and increases in yield when compared 
with calcium arsenate alone. Mixtures of calcium arsenate and nico- 
tine gave better aphid control and a greater yield than a mixture 
of the arsenate and rotenone. Late-afternoon applicptions of cal- 
cium arsenate and cube containing 0.5 percent of rotenone were more 
effective against aphids, and were followed by a slightly higher 
yield than early-morning applications, but the difference in yield, 
however, was too small for pignifiennce.— Young and coworkers ( 707-709 ) 
Aphis mai dis Fit oh, the corn leaf aphid 
This species is an insect vector of mosaic of sugar cane. Dust 
insecticides reduced the spread of mosaio in seed cane in some, but 
not in all experiments. Significant decreases were given by derris 
and pyrethrum but not by niootine sulfate.— Ingram and coworkers (310) . 
