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In Oregon use was made of a power duster that was attached to 
the front of a motor car and provided with a new type of hood to 
prevent the escape of the aphids. A 0.75-percent rotenone dust 
plus 3 percent soybean oil, applied at 35 pounds per aore, was the 
most effective. This dust can also be used to control aphids on 
trellis peas. Based on 4 years' investigations a spray that can 
be recommended for trellis peas contains 1.66 pounds of cube, derris, 
or timbo (4 percent of rotenone), 100 gallons of water and a wetting 
agent.— Gray and Schuh (242 ). 
An acetone extract of derris, used as a spray, was the most ef- 
fective insecticide used against the pea aphid in Maine .--Hawkins 
(272). 
With adequate equipment and proper insecticides the pea aphid 
can be controlled, and serious commercial losses prevented. Derris 
or cube dusts (not less than 1 percent of rotenone) applied at the 
rate of 35 to 40 pounds per aore were recommended in Utah.— Knowlton 
(342). 
Niootine applied by a vaporizer gave excellent control and was 
more widely used commercially in 1940 than any other treatment in 
Virginia. Derris or cube dusts with talc gave variable results. 
The duster boon should be completely enclosed and a 25-foot trail- 
er should be attached. Derris sprays with a suitable wetting agent 
gave adequate control of apliids.— Walker and Anderson (646 ) . 
Pyrophyllite (Pyrax ABB), flaky talcs, calcium carbonate, and 
gypsum produced high electrostatic charges which were reduced with 
the addition of rotenone, but when oil was added to the mixture the 
charge was greater than that produced by the diluent alone. Pyro- 
phyllite produced the highest charge while ground cube and derris 
roots produced a charge opposite to that of the diluents. The per- 
centage of kill usually inoreased in proportion to a general increase 
in the eleotrostatic charge produced by a mixed dust. These charges 
develop best on warm, dry days and this may explain in part why rote- 
none dusts give the best kill of pea aphids when applied in warm 
weather.— Wilson and coworkers (688 ) ; Wisconsin Agricultural Experi- 
ment Station (693, p. 48) • 
Dust mixtures containing niootine were recommended as a substi- 
tute for rotenone in combating the pea aphid, although rotenone is 
more effective. The recommendation, issued February 1942, specified 
(1) the use of a 1-percent rotenone dust applied at the rate of 35 to 
40 pounds per acre, or (2) the use of a 4-percent nicotine dust ap- 
plied at the came rate. The revised recommendation for the emergenoy 
