- 30 - 
effective as derris, assuming that the rotenone and total extractives 
are approximately the same in Doth samples. Derris or cube with a rote- 
none content of U percent was effective for pea aphid control when used 
at the rate of 2 or 3 pounds per 100 gallons of spray, assuming that the 
spray was applied at the rate of 125 to 150 gallons per acre. Aresket 
(liauid) used at the rate of 1 to 600 was used as a standard for compari- 
son with other spreaders. 
An extensive set of dust trials was planned for 1937 following 
limited work in 1936. Most of the dusts were made up to contain 1 per- 
cent of rotenone, other ingredients "being varied as desired. Variables 
included diluents, wetting agents, some suggested by Dudley and Bronson, 
and irritants such as nicotine and certain thiocyanatos. Results with 
rotenone-bearing dusts varied in 1937, as in 193&. * n many instances 
the results were excellent, but in certain experiments they were unsatis- 
factory. Apparently the poor performance was due to some weather condi- 
tion, such as absence of free moisture (dew or rain) on the plants, Hot- 
withstanding some very poor results obtained with rotonone-bearir.g dusts, 
it is believed that they have sufficient merit to warrant recommendation 
with reservation. The use of wetting agents or irritants in dusts for 
use on peas was not recommended. 
A committee of entomologists representing a number of the State 
experiment stations and the Bureau of Entomology and Plant Quarantine, 
of the United States Department of Agriculture ( 279 ) » a * the December 
193^ meeting of the American Association of Economic Entomologists at 
Atlantic City, issued the following suggestions for control of the pea 
aphid: 
Dusting with derris or cube: Preliminary experiments 
with these materials, with a carrier such as talc, conditioned 
with a spreader and wetting agent, have given satisfactory 
control. Their use is suggested only on an experimental 
basis. Such dust should contain approximately 1 percent of 
rotenone. 
Spraying with derris or cube: On the basis of ground 
derris or cube root containing U percent of rotenone, 3 pounds 
should be used per 100 gallons of water. Corresponding dilu- 
tions should be used with derris or cube containing more or 
less than h percent of rotenone. A spreader and wetting 
agent is necessary. The application per acre should be from 
150 to 200 gallons. Pressure should not be less than 300 
pounds. 
Cory and Graham (5_5) in 193^ reported that derris without a 
spreader gave poor control of the pea aphid, but with sodium lauryl sul- 
fate good control was obtained. Ten pounds of rotenone material (0.009 
percent rotenone in the finished spray) plus 1/2 pound of sodium lauryl 
sulfate were used to 100 gallons of spray. Rotenone remained effective 
against the aphids longer than did nicotine and soap. One year's experi- 
ence in Maryland with rotenone (without spreader) showed a slight decrease 
in aphid infestation and no increase in yield of peas, over the unsprayed 
plots. The next year's experience with rotenone (with spreader) showed 
