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Richardson ( 124 ) in 1932 compared the insecticidal value of rotenone, 
the oyrethrin's, and: nicotine against the greenhouse red spider mite. Tithout 
the addition of some netting agent, the oyrethrins, rotenone, and nicotine, 
even at high concentrations, have little toxicity to the greenhouse red spider 
mite. With the addition of 0.25 percent of potassium oleate soap, rotenone at 
0.02 percent Is slightly more toxic then the ^'yrethrins (0.02 percent); nicotine 
is much less toxic than either of these two*, aoproximately 0.66 percent being 
necessary to produce a mortality equivalent to that produced "by the above 
"mentioned concentrations of the other t*vb poisons-. With sulfonated castor oil 
as the 'letting agent,' the- ^yrethrins and rotenone' at 0.02 percent are about 
equivalent in toxicity; nicotine again is much less toxic, about 0.2 percent 
being necessary to equal the insecticidal efficiency of the other t^o at* the 
concentrations given above; ''Potassium oleate soao at 0.25 percent and 0.5 
percent is approximately equivalent in' toxicity to sulfonated castor oil at 0.5 
percent and 1.0 percent, respectively. Soap is more efficient than sulfonated 
castor oil as a wetting agent for rctenohe and the pyrethrins. With nicotine, 
however, the reverse appears to be true. 'Nicotine (1: 500) makes distinctly' 
alkaline the almost neutral 0.5 perce'nt of 'sulfonated castor oil, but has a 
relatively slight effect on the already' alkaline soao solution. Alcoholic 
extracts of the pyrethrins have an acidic effect rhen added to either sulfonated 
castor :oil or soap solution.- Acetone solutions of rotenone have very little 
effect on the pH-of either of these 'wetting agents. 
Hutson (76) in 1932 reported that' summer oils used at 1-percent strength, 
alone or in combination with bordeaux, arrnlied 2 or 3 times at intervals of 5 
days, controlled the greenhouse red snider in southwestern Michigan. Nicotine 
and Penetral, Derrisol.and soap, end t :lue vere three other successful sprays. 
Webster ( 158 ) in 1932 reported that freedom from red spider injury was 
conspicuous during the 1931 season on blocks of trees in the Wenatchee, Wash., 
experimental orchard, ^hich had." bpen "sprayed with rotenone, oil-nicotine, 'or 
the oil-pyre thrum combination.- 
• -Turner ( 146 ) in 1932 reported that cube extract 1:12,500, emulsified in 
1 percent of oil with pondered milk, killed 70 percent of the red spaders in 
greenhouses., whereas the check oil killed 14 percent.' 
G-nadinger (65) in the first edition of his "Pyrethrum Plovers," published 
in. 1933, cited unpublished work by Ginsbura; Hii-ch indicates that rotenone is 
more .toxic to red sliders" than are the oyrethrins. 
According to a. statement made by its manufacturers, Penick and Company 
( 119 ) in : 1936, Foliafume is a balanced pyr.e thrum- derris plant spray with 
spreader. The use of Foliafume at 1:400 is recommended for insects of inter- 
mediate, resistance, such as the red spider. At this concentration the avers 
mortality was .87 percent- after 48 hours. . ' 
Richardson (125) in 1934 reported tests "*ith an acetone extract of- derris 
containing 5.7 arc. of rotenone and 18.1 cm.- of total extractives per 100- re. 
In greenhouse and. small field tests derris extract <"ith snlfonr-.el castor oil 
