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Derris gave slightly "better results than cube when used in sprays. Dust 
mixtures containing either derris or cube root and having 0.5 percent ro- 
tenonc gave good control but wore slightly inferior to the sprays. There 
was no .apparent difference in toxicity "between derris and cube when used, as 
dusts in these tests. Beth clay and talc proved satisfactory as diluents. 
Howard (198) in 1935 reported tests made at Columbus, Ohio, the 
previous year with insecticides against the Mexican bean "beetle. Satis- 
factory control was obtained with suspensions of derris root powder and cube 
root powder in water at dilutions of 0.01, 0.015, 0.02, and 0.025 percent of 
rotenone. Fairly satisfactory results were obtained with derris sprays 
containing 0.005 percent of rotenone. The incorporation of various wetting 
agents, spreaders, and stickers did not improve the efficiency of these spray 
suspensions. In general, cube proved to "be approximately equal in effective- 
ness to derris when tested at the same dilution of rotenone. Derris dv.st 
mixtures and cube dust mixtures containing 0.4, 0.5 and 0,75 percent of ro- 
tenone, respectively, with various diluents, all gave satisfactory control. 
As a result of special tests of various diluents, it was concluded that it 
was not important to obtain any particular diluent for use with derris or 
cube dust, provided such diluent is honalkaline in character. The results 
indicated that talc-flotation sulphur (50:50), wheat flour, ground [pyre- 
thrum] marc, talc, bentonite, and. finely ground dusting sulphur in the order 
named, with the last two almost equal in effectiveness, were as good as, or 
slightly superior to, any of the diluents 'tested. In general, derris dusts 
appeared, to be slightly superior to cube dusts in effectiveness. 
Howard, Brannon and Mason (199) in 1936 recommended derris or cube 
spray as the best control measure for the Mexican bean beetle. Three pounds 
of powder (containing 4 percent rotenone) per 100 gallons gives a rotenone 
content of about 0.015 percent. The treatment should be started, when beetles 
are found, in the field and should be repeated at inter zeds of 7 to 10 days. 
Dusts containing 0.5 percent rotenone nay be used at the rate of 20 to 25 
pounds to the acre per application. Sprays are recommended in preference to 
dusts for bean beetle control, since spraying v/ill give better control and 
longer protection to the plants. In the case of hone-nixed dusts, cither 
talc, dusting sulphur, infusorial earth, kaolin (china clay), or other finely 
ground inert clay, gypsum, diatonaceous earth, wheat flour or tobacco dust 
may be used as a diluent or carrier, but recent experiments have ind.icated 
that talc is the most satisfactory. Dusts containing 0.5 or 0.75 percent 
rotenone should not be used for making sprays. Begin spraying when the 
adults are found, in the field or when the eggs of the beetle become numerous 
on the undersid.es of the leaves. One to three, seme times four, applications 
are required., depending on the abundance of the insect. 
Howe (204) in 1936 reported tests made at Clarksville, Tonn. , against 
the tobacco flea beetle, Epitrix parvula Fab., which indicated that a cube 
root d.ust mixture having a rotenone content of approximately 1.5 percent 
was the most toxic of the materials tested against the flea beetle on dark- 
fired tobacco, but that a similar dust mixture containing 2 percent rotenone 
was most efficient in the tests with Burley tobacco. In general, however, 
