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not cause detectable injury to the cucumber -plants, but those to which the 
thiocyanate spray was applied suffered some injury directly attributed to 
the treatment. 
Weigel end Johnson ( 162 ) in 1940 reported that white- oil emulsion is 
more effective than sulfonated castor oil as a spreader for derris-pyre thrum 
spray against red spider. Small-scale toxicity tests against Tetrenychus 
bimaculetus were made on potted cucumber seedlings, and "ere designed to 
determine whether certain spreaders could be substituted for sulfonated 
castor oil in the derris-pyrethrum-sulfonated castor-oil sr>ray without 
reducing the effectiveness of the spray combination against this pest. The 
test plants were uniformly treated by spraying both sides of all leaves with 
a small atomizing electric sprayer held at a. distance of 15 feet from the 
leaves during application. In all derris-pyre thrum spray mixtures tested the 
concentration was 0.0056 percent of rotenone and 0.01 percent' of pyrethrins, 
m hile the derris spray alone contained 0.0056 percent of rotenone. All 
mortality counts of red spiders were made 2 days after treatment. The 
mortality of red spiders ranged from 71.9 to IOC percent for the 11 spray 
combinations used in the tests. Both the derris spray and the derris-"oy- 
rethrum spray, to which had been added white-oil emulsion, 1:100 by weight, 
gave 100-percent mortality of the spiders, as compared with 82.2 and 83 
percent from derris-pyre thrum sprays to which had been added sulfonated 
castor oil at the rates of 1:200 and 1:400 by .volumi, respectively. 'Water 
sprays containing only the white-oil emulsion at concentrations of 1:100 and 
1:200 by weight resulted in mortalities of 97 a 3 and. 92,1 percent, respective- 
ly. A derris-pyrethrum spray containing sodium oleyl sulfate 1:1,000 by 
volume gave a mortality of 78.7 percent, whereas one containing the sodium 
oleyl sulfate plus synthetic resins, 1:1.000 by volume, gave 87.6 percent 
mortality. Another derris-pyro thrum spray containing sodium lauryl sulfate, 
1:3,000 by weight, resulted in a mortality of 71,9 percent; for the same 
period of observation there was an average mortality of 5.3 percent of the 
red spiders on untreated cucumber seedlirgs and 23.3 percent on plants 
sprayed with plain water. Apparently the white-oil emulsion 1:100 by weight 
was considerably more effective than sulfonated castor oil 1:300 or 1:400 in 
the derris-pyrethrum spray. The white-oil emulsion alone, 1:100 or 1:2CC by 
weight, was very effective against the spiders. There ^cs probably little, 
if any, real difference between the effectiveness of sodium oleyl sulfate 
1:1,000 by volume, sodiua oleyl sulfate plus synthetic resins 1:1,000 by 
volume, sodium lauryl sulfate 1:3,000 by weisht, and sulfonated castor oil 
1:300 or 1:400 by volume, in the rotenone-pyrethrum si)ray. 
Crosby, Chupp, and Leiby (47) in February 1939 discussed the control of 
diseases and insects affecting vegetable cro-ns on Lon< Island. Experimental 
results indicated that the red spider mite on lima beans can be controlled 
by dusting with a sulfur-rotenone dust containing 0.75 percent of rotenone. 
The rotenone is included in the formula under the assumption that the vines 
would be dusted for the control of. the Mexican bean beetle at the same time 
that efforts to control the red spider mite are being made. If a spray is 
desired, 4 pounds of rotenone-bearin^; powder (4 percent rotenone) in 100 
gallons of water probably will control this pest satisfactorily. The dust 
