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The Ohio Agricultural Experiment Station ( 116 ) in 1934 reported that 
Rotecide at 1:400 in water £ave a 92-percent kill of red spider with no 
observable injury to the soybean slants in a greenhouse* 
Howard, Mason, and Davidson (74) at the meeting of the ^hio Vegetable 
Growers Association held January 31, 1935, at Columbus, Ohio, reported that 
tests "dth derris dust had been made against the red spider, but in e/ery 
instance the infestation was too li^ht to draw conclusions. 
The Rubber Service Laboratories Company, Inc. ( 131 ) in 1934 and again (132) 
in 1935, issued suggestions for the use of Areskap and Aresket in insecticidel 
sprays. A mixture of 7 parts by weight of derris resin, 33 parts by weight of 
Dry Areskap, end. 60 parts by weight of either pine oil or oleic acid has been 
found to be effective at 1:400 for control of the red spider. 
The Polytechnic Institute of the Alabama Agricultural Experiment Station 
(4) in 1935 stated that derris mixed with sulfur is effective against red 
spiders. Derris dust should contain at least 0.5 percent of roten:ne. 
Weigel and Richardson ( 165 ) in 1935 reported that the proportion- of 
sulfonated castor oil is en important factor in the. effectiveness of derris 
sprays against the red spider. Tests conducted against red spider mites at 
Earberton, Ohio, indicated that a spray composed of derris-root powder in 
water (rotenone approximately 0.0034 percent), which had not proved entirely 
effective, showed a marked increase - in effectiveness when the proportion of 
sulfonated castor oil was increased from 1:400 to 1:300. With this proportion, 
kills of 98.4 percent of the adults and 95.4 percent of the nymphs were, 
obtained. It was observed that increasing the rotenone content to 0.0052 
percent without increasing the proportion of sulfonated castor oil did not 
appreciably increase the effectiveness. Similar results were obtained when 
cube— root powder in r-ater, containing approximately 0.0095 percent of rotenone, 
was used with the sulfonated castor oil. 
Murphy ( ill ) in 1936 reported that beta-butoxy-beta'-thiocyano-diethyl 
-ether (the active constituent of Lethane 420 and Le thane 440) was more 
effective against the greenhouse red spider than pyre thrum or derris sprays. 
One commercial derris spray killed 61 percent of the sliders at 1:200 and 
another killed 74 percent at 1:500; whereas the tfaiocyanate killed 76 percent 
at 1:1,000 and 95 percent at 1:800, when used with a spreader at 1:200. 
The Ohio Agricultural Experiment Station ( 117 ) in 1936 reported that for 
the control of the red spider the rotenone sprays were the most satisfactory 
of the materials used, when effectiveness, freedom from pi ?n t injury, and 
costs are all considered. A new sulfated alcohol spreader and sticker, when 
used at 1:500 with various commercial rotenone sprays, served to increase the 
kill over tha t produced by the same rotenones when used with various soaj 
spreaders, at 1:250, by approximately 11 percent in a number of tests. 
