Experiments by the Bureau of Entoinology and Plant Quarantine, in 
cooperation mth the Idaho Agriciiltv.ral Sxperiinent Station (2ll) « in 1957 
reported that successfxi.l control of the pea t.-eevil may be expected from 
the use of derris dust# Peas dusted T/ith derris and tobacco dust were 
90,62 percent free from the T/eevil in the green-pea stage and 98,77 per- 
cent free in the dry-pea stage. Other effective insecticides vrere crj-'O- 
lite and derris dust vdth diatonaceous earth, and derris dust \vith sulfur. 
Calcium arsenate v.'as the least effective of B.ny- of the dusts used. 
The Oregon Agricultural Experiment Station (310) in 1937 reported 
that a method of controlling the pea vreevil oy the "application cf rotenone 
dusts had been discovered, 
Ballard ( 2_5 ) in 1938 reported that the control of the pea -vvoevil in 
c om;me re ial- scale plantings was achieved the past year by growers of 22,000 
acres of peas in Umatilla County, Oreg, This ^vas done by applying a talc 
dust containing 0,75 percent of rotenone by means of a hood-t^,^e duster. 
Drindley (_50) in 1938 reported that laboratory tests against B, 
piso^rum at the Moscov.-, Idaho, laboratory gave the following results: (l) 
Distinct differences were shoT-m to exist betv/een the mortality obtained 
mth dust mixtures containing 1, 0,75, and 0,5 percent of rotenone, 
respectively. Much less difference v/as noted in the toxicity oi dusts 
containing 1 percent and 0,75 percent than betvifeen those containing 0.75 
and 0,5 percent of this ingredient, (2) A cube-dust mixture with diatoma- 
ceous earth as a carrier did not give so hi^-h a mortality as did cube with 
talc as a carrier, (3) The addition cf 2 percent of peanut oil, 1 percent 
of sodiLim oleyl sulfate, and 0^5 percent of Y^ter to cube in talc did not 
increase its toxicity, (4) A dust containing 0,005 percent of sulfur 
nitride t/as nontoxic to the weevils, (5) The addition of 0,225 percent 
of pyrethrins to a cube dust in talc, containing 0,5 percent of rotenoiie, 
markedly increased the toxicity of the dust, (6) Additional data were 
accumulated to indicate that at least a part of the toxic effect of 
rotenono-containing dusts to the pea weevil is due to its contact properties 
Chamberlin and Gray (7_8) in 1938 reported that the pea weevil in 
Oregon can be best controlled by the use of dust mixtures containing 0.75 
percent of rotenone. From one to three applications to the infested fields 
are necessary, tho first being m.ade when the peas are in bloom and before 
the pods have set. Dusts should be applied at the rt'te of 20 to 25 pounds 
per acre. 
Hinman and Fisher (187) in 1938 reported that during the sui-nmer of 
1937 a dust containing 1 percent of rotenone, applied at the rate of 25 
pounds per acre, satisfactorily controlled the pea vreevil in Oregon and 
Washington. The use of hoods on the large dusting machines increased the 
efficiency of the dust, T.rhich should contain not less than 0,75 percent 
of rotenone. 
Tho Idaho Agricultural Experiment Station (215) in 1938 reported 
that rotenone-bearing dusts applied v/hon pods began to x'orm and at inter- 
vals •v*.en the population was increasing, .continued to give a high por- 
centage of control o" adults. 
