In the wastern Oregon and Washington pea-growing area whero the pea- 
fields are in smaller units, the entire field was treated and weevil 
infestation Fas reduced to a minimum, 
Brindley (51) in February 1939. reported the results of tests 
to control the pea weevil. Laboratory .tests wf^rn conducted in 1934 
with fo'or insecticides — calcium arsenate, "bari-om fluosilicate, a dust 
containing 0.45 percent of pyr^-thrins, and a dust containing 1 pnr~ 
cent of rotenone in thn form of powdered derris root. Adult weevils 
were placed on "blossoms picked from plots that had T3een treated with 
these materials at the rate of 20 pounds p-^r acrf^, dustf^d weevils 
were placed on untreated "blooms, and we-'^vils forced to walk a distance 
of 2 inches across a glass surface dusted with each of the materials 
were placed on undusted "blooms. One application of calcium arsenate 
or TDaxium fluosilicate, even though thoroughly applied, did not kill 
all the weevils in 24 hours, whr^reas the application of derris and 
pyrethrum dust killed all the weevils. When the materials were applied 
directly to t"ne weevils, practically the same results were recorded, 
Brindley and Linduska (53 ) of the Moscow, Idaho, lahoratoiy, 
reported in Fe"bruary 1939. that experiments with dust mixtures contain- 
ing rotenone against B» pisorum on garden plots in 1938 showed that 
the addition of various conditionf^rs to the dust mixtures only slightly 
increased their efficiency, as compared with dust mixtures composed 
solely of finply ground derris or cuhe root with talc or diatcmaceous 
earth as a diluent. The results of th^se experiiri^nts may "be s\iramarized 
as follows: (l) Bust mixtures containing 1 percent of rotenone with 
talc as the diluent, which is now "being used commonly "by the growers, 
gave a control of 95.6 percont when applied to plots harvested as green 
peas and 94.6 percent in plots harvested as dry peas, as compared with 
comparable ontreat^^d plots. (2) A dust mixture containing 1 percent of 
rotenone with diatomaceous earth as a diluent, also "being used cpmrnonly 
"by the growers, gave a control of 98,9 percent in the green-pea plots 
and 95,8 percent in dry peas. (3) A dust mixture containirfg 1 percent 
of rotenone with talc as a diluent, plus 1 percent of Ipjnpblack by 
weight, gave a control of 100 percent in thp gre^^n-pea plots and 90.4 
percent in dry peas. (4) A dust mixture containing 1 percent of rotenone 
plus 2 pnrcent of peanut oil, 1 percent of sodium oleyl siilfat'e as a 
wetting agent, ejid 0.5 percent of water gave o. control of 100 percent 
on green peas and 96,1 percent on dry peas. (5) A mixture containing 
ea'aal parts by weight of a dust mixture containing 1 percent of ' rotenone 
with talc as the diluent and a dust mixture containing 0.45 percent of 
total pyrethrins with diatomaceous earth as the diluent gave a control 
of 99.6 percent on green peas and 89.9 p'-rcent on drj^ peas. 
Haude ( l8l ) in 1939 recommended cube or derris dust (0,75 to 1 
percent rotenone) at 20 to 25 pounds per acre, applied under a hood for 
control of the pea weevil. 
Hinman, Fisher, and Brindley (l88_) reported in 1939 that a 
survey of the Blue Mountain area of Washington and Oregon revealed 
that more than four ti-es as much dust mixture containing rotenone 
was used against the pea weevil in this area in 1938 as in 1937, 
