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A 0.6-percent rotenone dust with 3 percent of Lethane 384 and 
a 0.4-percent rotenone dust with 2 percent of Lethane gave promising 
results near Norfolk, Va.— Walker and Anderson (647 ) . 
Many factors contribute to the effectiveness of rotenone, three 
of which include the diluent selected, the equipment used in apply- 
ing dusts, and the care employed when dusting. As a class, talcs 
appear to be the best diluents although none of them equalled Pyrax. 
Adding 2 percent of lubricating oil increases the electrostatic charge 
of talcs but reduces the charge of some materials. When 22 samples 
of talc and 3 of pyrophyllite were examined only 5 of the former 
and 1 of the latter were compatible with rotenone. The failure in 
the past to secure consistent control of insects with derris and cube 
dusts was mainly due to the use of unsuitable diluents and methods 
of application. When a compatible diluent was used as a carrier and 
oil was added the dust was highly toxic to the pea aphid. With com- 
patible diluents and optimum application methods significant re- 
ductions in rotenone content can safely be made with no loss in kill. 
A 1- or 0.75-percent rotenone content in these diluents are not sig- 
nificantly better than 0.5- or 0.25-peroent rotenone duets. Pyro- 
phyllite was better than clay as a diluent for cube dust. All dusts 
with a rotenone content of 0.6 to 1 percent to be used for control 
of the pea aphid should be conditioned with 1 or 2 percent of oil, 
such as soybean oil.— Wisconsin Agricultural Experiment Station (696 , 
p. 53) j Wilson and Bender (685) ; Wilson and Janes (689-691 ). 
In 1943 it was concluded that 5 years* work in Maryland with 
derris sprays had provided a satisfactory monetary return. A 1-per- 
cent rotenone dust gave as good results as a derris spray but cube 
sprays did not give adequate control. The effectiveness of rotenone 
inseoticides varied from year to year. There was a strong relation- 
ship between toxic action of the rotenone and adequate rainfall both 
preceding and following the treatments. Nicotine sprays were better 
than derris sprays, and the nicotine vapor-fumer gave the highest 
kill.— Ditman and coworkers (144) . 
The most satisfactory treatment for the pea aphid on peas in 
Wisconsin was the use of a dust containing at least 0.5 percent of 
rotenone mixed with pyrophyllite or talc, applied at the rate of 35 
to 40 pounds per acre. Directions were given for increasing the 
effectiveness of this mixture by adding nicotine or light lubricat- 
ing oil. Derris or cube sprays containing 3 pounds of powder, 4 to 
8 ounces of a suitable wetting agent, in 100 gallons of water were 
also effective when applied at the rate of 125 gallons per acre under 
a pressure of at least 300 pounds.— Dudley and Bronson (149) . 
