- SI - 
Rotpnone sDrays or dustc wc-re reconmcndrd "by Par>s and Picrstorff 
( ?i2 ) in iq;^s. 
Roark ( 327 '' in 1938 referrrd to the work of Howp.rd ( 19O ) . who found 
derris dust superior to cu"be dust, but "both derris and cube sprays equally 
effective ajgainst the Mexican "boan "boetle; also tc th? South Carolina 
Agricultural Experinent Station ( 3U7 ) ^ v;hich found derris and cube equally 
good whether "^n thr forti of dusts or sprays; and to the Nev York Agricult- 
ural Experiment Station ( 3OI ) . which found derris bcttrr than cube, whether 
in th'-^ form of dust«5 or sprays. 
The South Carolina Agricultural Experiment Station ( 331 ) in 1^38 
reported that the control recommendations as first advocated in 193^ 
have been v.^ry effective in all tests at this station. The recommended 
treatment is to spray with a mixture consisting of 3.5 pounds of 5-p<:''rcent 
rotenone in 100 gallons of water or to dust with a mixture of 15 pounds 
of 5-pprcent rotenone and S5 pounds of talc or inert clay. 
Todd ( 37'^ ) in 1938 reported that derris-talc dust containing 0,75 
percent of rotenone applied to bean foliage did not afford protection 
against the Mexican bean beetle beyond 7 days of exposure under field 
(sun) conditions. In the shade derri? was effective for 2 weeks or as 
long as the' plants held up. A spray containing 0.018 percent of rotenone 
was less effective than the dust. 
The United State? Bureau of Entomology/ and Plajit Quarantine (398) 
in 193^ gave the results of much v;ork vrith rotenone products. Field 
experiments in Ohio and Virginia on beans grown for the greon-bean market 
or for canning showed conclusively that the Mexican bean beetle can be 
satisfactorily controlled b." the use of sprays or dust mixtures contain- 
ing rotenone derived from derris, cube, timbo, or devil' s-shocstrings. 
In Colorado the. results from test on irrigated beans grovm for the dry- 
bean market demonstrated that sprays containing derris and cube gave better 
results than any oth-r materials tested, and thpt cryolite sprays gave 
the next best results. 
Wallis (U09 ) in 1938 summarized the res'ilts of tests performed with 
insecticides against the Mexican bean beetle in Colorado in 1937. ^p 
rer)or.trd that sprays conta'ining derris and cube gave better results than 
anv other materials tested, the increase in yield ranging from 10, U to 
^8,7 percent over the check plots, 
Brannon i]^) in 1939 summarized thr results of an experinent con- 
ducted on Fordhook lima bean<= at I'forfolk, Va, ^ late in the summer and 
early in the autumn of 193S- Dx^st mixtures or sprp. s containing cryo- 
lite con,trolled successfully an infestation of Epilachna varivestis in 
association with Heliothis ob so l eta (F,), The cryolite-dust mixtures 
consisted of 60 parte^ of cryolite to Uo parts of sulfur or of talc, by 
weight. The cryolite spra. s were made up at the rate of 3 pounds of 
cryolite to 50 gallons of water. Cryolite dusts and sprays increased 
the yield R-moroximatel" 70 percent, as comparvd with the check, whereas 
plots to which sprays of derris or cube had b'en aioplied showed yi:^ld 
increases ranging from 30 to ^0 percent. In view of t'le fact that the 
Mexican bean beetle infestation in the field where the experiment was' ^^taged 
was not usually severe, the larger yield increases from the uso of cryolito 
