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showed promise in control of red slider mites on roses and other plants. 
Richardson (126) in 1935 reported on the control of the red spider on 
greenhouse plants. Sprays made from commercial acetone extracts of derris 
(see Jour. Econ. Ent. 26: 995. 1933) and sulfonated .castor oil (turkey-red 
oil) have been found to.be toxic to the common red spider in smsll-scele 
tests on infested tomato plants in the greenhouse. Dilutions giving rotenone 
contents, respectively, of 1:15,000, 1:25,000, 1:50,000 'by Height and total 
extractives of approximately 1:4,000, 1:6,250, end 1:12,500 in water containing 
0.25 percent (l:400) by 'volume of sulfonated castor oil, 75-pereent product, 
gave 100. 0-, 98.3-, and 93.7-percent mortality. Considerable trouble has been 
experienced with commercial acetone extracts that have deteriorated during . 
storage. They are not only much less effective in insecticidal and acaricidal 
action, when added to the spray, but they produce large quantities of resinous 
precipitates, even though first diluted with an equal volume of acetone. These 
precipitates tend to clog the sprayer and pump valves, making such extracts 
unsuitable for practical use. Undeteriorated derris extracts are much more 
toxic to -the red s-oider than are equivalent quantities of pure rotenone. A 
dust containing derris extract in diatomaceous earth, orepared to give 0.5 
percent of rotenone or 1.8 percent of tcrtal derris extractives, had little effect 
against the red spider on hollyhocks in the greenhouse (2 percent kill of 321 
mites). • : 
Suspensions of finely ground- derris root (2.9 percent of rotenone and 16.7 
percent of total carbon tetrachloride extractive's) at a concentration of 0.25 
percent by weight (rotenone approximately 1:14,000) in combination with 0.25 
percent by volume of sulfonated castor oil (1:400) were found to give very high 
kills of the red spider on cucumber plants. Two series of small-scale' tests, 
5 replications each, killed averages of 92.4 and 99.2 percent of the adults and 
86.2 and 97.6 percent of the nymphs. More sulfonated castor oil (0.5 percent) 
was used in the second series. These sprays also killed the onion thrips__jaiL. 
cucumber. Suspensions of powdered cube- root (5.3 percent of rotenone and 17.3 
percent of total carbon tetrachloride extractives) at the rate of 0.25 percent 
(rotenone approximately 1:8,000), in combination with 0.25 percent by volume of 
sulfonated eastor oil, also gave high mortality. 
Cube killed 97.2 percent of the adults end 96.6 percent of the nymphs, as 
compared with 99.2 and 99.5 percent kill, respectively, for adults and nymphs 
by the same Concentration of derris' with 0.5 pereent of sulfonated castor oil. 
The derris-root powder suspensions (0.5 percent by neieht) ™ith sulfonated «astor 
oil (0.25 percent) seemed to be stable, as they were just as toxic to the mites 
6 days after preparation as Hien freshly prepared. There appeared to be no 
advantage in soaking the powder in cold ™ater before spraying, or in boiling 
the suspension (in 1/8 the final volume of spray) for a few minutes and then 
diluting it in the spray. The suspension was much less effective when used 
without a wetting agent. In a heavily infested cucumber greenhouse, the same 
derris at -a concentration of 0.12 percent (rotenone = 0.0034 percent) plus 
■sulfonated castor oil at 1:300 killed 98.4 nercent of the adults and 96.4 
percent of the nymphs. This work by Richardson was reviewed by Roark ( 128 ) in 
1938. 
