- 28 - 
White (305) in April 193^ issued suggest ions en the Use, of derris 
sprays for -control of the pea aphid. Tor this purpose derris should con- 
tain k percent of : rotenone and he used at the rate of 2 pound? per 100 
gallons. At least 150 gallons of the spray should he applied per acre 
under a pressure of not less than 250 pounds, when the plants are dry. A 
wetting agent should be used at the rate of about 1/2 pound dry veight 
per 100 gallons of water. Sodium lauryl sulfate and sodium oleyl sulfate 
are suggested a;- suitable wetting agent?, and a sulfated phenylphenol at 
1:1,500 (dry basis) has been used successfully. 
The New York Agricultural Experiment Station ( 213 , 21>) in I936 
reported that derris was being tested for the control of the pea aphid. 
In 1937 this station stated that rotenone sprays, properly applied with 
adequate, equipment-, pre.'"". v effective in killing the pea aphid, but 
that rotenone dusts had net been tested in . the field sufficiently to bring 
out all their possible limitations. 
The United States Department of Agriculture, Bureau of Sntcmology 
and Plant Quarantine (278) in its annual report for 1 Q 35 stated that the 
pea aphid caused heavy losses to the pea growers in Wisconsin, Kew York, 
and Ohio. The investigations consisted -primarily of fi-ld-plot tests 
with several insecticides and, while the results to date are only pre- 
liminary and cannot be used re. a oasis for recommendations on pea. aphid 
control, the indications are that a derris-powder sora.y may be useful 
against the pea aphid. 
The Bureau of Entomology and Plan^c Quarantine (280) in its annual 
report for 13 7 b stated that encouraging results in the control of the pea 
aphid wre obtained in 1935 with sprays containing derris, end special 
field experiments were conducted with derris sprays and derris dusts in 
California, Florida, and Virginia late in the winter and in the spring of 
1939* J ~ r - r results of these field tests indicated that derris sprays were 
effective in controlling the pea aphid and that, under favorable condi- 
tions, ins idss containing rotenone- the active ingredient of derris 
and cube, had -• r°sidua.l effect that protected the treated plants from 
severe damage for an extended -neriod. It was determined that, in general, 
sprays cr dusts containing nicotine have a '/ore repid actioa against the 
pee. aphid than insecticides containing rotenone, but the latter hrve a 
much longer residual effect. This residual effect of rotenone-containing 
insecticides,, as observed in field tests, was substantiated by laboratory 
studies. Continued field work late in the spring of 193^ derr^nstrated 
that a derris dust containing a specially ^erepa.r r d spreading agent yielded 
result'- comparable: to those from a derris spray, the dust being prepared 
by atomizing a sodium oleyl sulfate into the derris-dust mixture While it 
was being revolved in a. steel-drum ball mixer. The Bureau ( 281 ) in its 
1 G 3? annual report staged that cube or derris dusts plus sodium oleyl sul- 
fate are effective against pea aphids and leave no rcterone or other con- 
stituents in peas taken from treated plants. In its 193? annual report 
the Bureau ( 283 ) gave the results of much work with rotenone products. 
During the springs of 193 7 ar -d 193? ^ ae P ea aphid was particularly trouble- 
some in Maryland, Delaware, end New -Jersey. Investigations were continued 
in Wisconsin on the central of this u r st. In these control t^sts emphasis 
was placed on the time of tr.:atm~nt for maximum benefit in protection of 
the crop. Field and laboratory t~sts were continued with derris and cube 
. 
