- 27 - 
under Wisconsin conditions. The analysis demonstrated further that the 
wind velocities remained within a range of from to h miles per hour for 
consecutive oeriods of 3 hour's or more at a time approximately two and 
one-half times as often during the night as during daylight hours. These 
data indicate the desirability of applying dust mixtures for nea aphid 
control during the night, whenever conditions will permit. 
Bronson and Stone (29) in I93S reported that, in an extensive 
series of greenhouse tests with several combinations of derris-dust mix- 
tures against the pea aphid, a derris-dust mixture containing Q.k percent 
of rotenone, with talc as the diluent and conditioned with sodium oleyl 
sulfate as a wetter and spreader (1 percent), plus a crude peanut-oil 
emulsion (2 percent), gave a satisfactory mortality of the pea aphid 
through all the ranges of relative humidity from 20 to S5 percent. The 
application of dorris-dust mixtures that did not contain any conditioning 
materials resulted in a low mortality of the pea aphid at all the ranges 
of relative humidity encountered. The application of derris-dust mixtures 
containing sodium oleyl sulfate (1 percent) as a wetter and spreader, 
but without crude peanut-oil emulsion, gave a low mortality of the iaea 
aphid at lev; relative humidity and a satisfactory mortality of the test 
insects after the expiration of U days in instances when the relative 
humidity was 50 percent or higher. It was concluded, on the basis of 
these tests in the greenhouse, that derris-dust mixtures containing the 
sodium oleyl sulfate as a wetter and spreader were decidedly more toxic 
to the pea aphid than a dust mixture not containing this ingredient; 
whereas the dust mixture containing this same wetter and spreader, plus 
a crude peanut-oil emulsion, was greatly superior to the dust mixture 
that did net contain this vegetable oil. These results corroborate pre- 
viously reported findings of Howard and Fulton, of the Columbus, Ohio, 
laboratory, that the addition of peanut-oil emulsions to sprays or dust 
mixtures greatly increased their efficiency against large plant bugs. 
If the results of these greenhouse tests are borne out under field condi- 
tions the effectiveness of dust mixtures containing rotenone for use 
against the pea aphid may be increased greatly by the addition of peanut- 
oil emulsion; but thus far results in the field have varied with humidity. 
The Secretary of Agriculture (27*0 in his 19 7 6 annual report wrote 
as follows: 
Laboratory and field tests with organic insecticides, 
particularly derris and cube, have brought many modifications 
in the recommendations for the control of certain insect nests. 
It has been demonstrated that these insecticides, which do not 
leave residues objectionable from the standpoint of human»health, 
can be effectively used against a number of different truck-crop 
pests. * * * The further usefulness of these recently developed 
materials is evidenced by the determination that one application 
of sprays or dusts of derris or cube is effective against the 
pea aphid over a longer period than other recommended material, 
such as pyrethrum and nicotine. 
This statement also appears in the Yearbook of the Department of 
Agriculture (29£) for I937 . 
