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results of tests made in 1935 at Madison with derris (rotenone 3.7 per- 
cent total carbon tetrachloride extractives l6.1 percent) against the 
pea aphid. Three series of experiments were conducted: (l) In a green- 
house late in the winter and early in the spring, (2) in the field during 
the normal pea-growing season, and (3) in the field late in the season 
on late-planted peas. The greenhouse tests demonstrated that ground derris 
as a sr»ray applied at the rate of from l-l/2 to 5 pounds per 100 gallons 
of water (0.006 to 0.022 percent rotenone), with a spreader and wetting 
agent, killed nearly 100 percent of the aphids on the treated plants. 
The aphids died throughout a period of from 3 to 5 days , and practically 
no reproduction occurred in the interim. 
Many summer field tests on both small and large plots demonstrated 
that around derris as a spray, applied at the rate of from 1/k pound to 
5 pounds per 100 gallons (0.0009 to 0.022 percent rotenone), with a 
spreader and wetting agent, killed more than 90 percent of the aphids 
on the treated plants; that from 3 to 5 days were required to obtain 
the maximum mortality; and that little or no reproduction occurred during 
that period. In these tests the application of derris sprays increased 
the yield of shelled peas approximately 8S percent over that of untreated 
checks. 
A large number of tests on late-planted peas revealed that derris 
as a snray, with a spreader and v/etting agent, applied prior to aphid 
infestation protected the plants from appreciable damage for several 
weeks and resulted in an ultimate infestation considerably lower than 
that in the untreated checks; that heavy applications of derris sprays 
after the incidence of an infestation protected peas from damage from a 
commercial standpoint for nearly a month, enabling them to produce a 
normal crop of pods; that heavy applications of derris sprays with any 
one of several spreaders and wetting agents, made after the infestation 
had become heavy, killed approximately 95 percent of the aphids; that 
derris sprays controlled the aphid more ouickly and to a higher degree 
than did derris dusts (rotenone 0.^- percent); and that concentrations of 
derris as low' as lA to 1/2 pound (0.0009 to 0.0019 percent rotenone) 
per 100 gallons, with spreaders and v/etting agents, killed approximately 
as large a percentage of aphids as did 3 pounds per 100 gallons. Wetting 
and spreading agents tested included a pine-oil product, diphenyl butyl 
sodium sulfonate, sodium lauryl sulfate, and sodium oleyl sulfate. 
In 1Q37 the ^-ame authors summarized the results of field experi- 
ments with derris and cube against the' pea aphid. Dusts tried included 
derris powder plus talc, cube powder plus talc, and derris powder plus 
talc and sodium oleyl sulfate, all diluted to a content of 1 percent 
rotenone. In order to be effective a spray of cube or derris should con- 
tain at least 0.005 percent of rotenone. The dusts were applied at the 
average rate of U6 pounds per acre; the sprays, at the average rate of 
lUU. gallons per acre. Increases in yield from five dusting tests ranged 
from 59 to 2U0 percent and averaged 138 percent. Increases in yield from 
three spraying tests ranged from 96 to 109 percent and averaged 101 per- 
cent. A limited number of tests indicated no difference between the 
effect of derris snd^ of cube sprays. In the sprays various wetting agents 
were tried, including b>utyl diphenyl sodium sulfonate. In comparable 
dusting tests the special derris-talc dust -was appreciably better than 
