- 76 - 
ExpoTiments performed in IQ^? s,t Soi-'.th Poiiit, Ohio, against 
Spilachna. vp.rivf s tis "by Hov/?.rd and Mason (IQ9) ga.ve the following 
rcfiults v/ith the v^riowi innecticides tostcd" Phpnothi&zine at 2 
pounds to 50 gallo-ic of water gave good control, 'out sl5.ght plant 
injury result ?rV derris, cuop^ ciirilDo, and dovil' i-- shoestrings gave 
good control ao a ccnccnTr^-faion of 0^015 percent of rotenone and usually 
at concentration of 0,01 percent of rotnnono, l.fliile the use of a varnish 
sticker with derris and cuhe increased the degree of control in one instance ^ 
no increase could he noted in two other experiments. The use of sulfur 
with derris or cube sprays, and its use as a diluent with dust mixtures of 
these materials, does not consistently result in improved control in Ohio; 
however, its use farthi r east usually results in "better bean crops. 
Hutson ( 213 ) in 1937 recommended derris dust (0.6 percent of 
rotcnonc) for the control of the Merican bean beetle. 
A derris dust containing 0.75 percent of rotenone killed 97 pf^rcent 
of the larvae and 87 percent of the adults on lima beans, A spray of 
derris powder (U percent of rotenone) at the rate of 2 pounds per 100 
gallons of water plus* about 2 pounds (dry basis) of coconut-oil soap 
killed QO percent of the larvae and 9^-^ percent of the adult «;. — Manschke 
( 272 ) in 1937. . , , 
Derris dust has given satisfactory results on the Mexican bean 
beetle. — Nevr Jerf^ey Agricultural Experiment Station ( 297 ) in 1937. 
The New York Agricultural Experiment Station (3OI) in 1937 made 
comparative tests of derris, c^lbe, and timbo powder having about the 
same content in active ingredients in spray and dust mixtures for the 
control of the Mexican bean beetle. The results showed that all three 
povfders vihen used at comparable strengths in terms of active ingredients 
were efft^ctive, a slight superiority favoring derris. Spray mixtures 
containing 2 to 3 pounds of good-grade powdered root in 100 gallons of 
wat--^r vrith sticker gave satisfactory results. Sprays during the current 
season vrere more beneficial to plant growth than were dusts. Of the dust 
mixtures tested, those containing 0,5 and 0,75 percent of rotenone gave 
the best results. It is interesting to note that the yield of snap beans 
from plants effecti-'-el;' sprayed or dusted did not inv^^riably result in 
markpd increases in yield of pods, Prom such evidence it seemed highly 
probable that to formulate a rational method of control for the Mexican 
bea.n beetle emphasis should be placed mo:t:e on the^mnking of a few oppor- ' 
tune applications and less on the necessity for fulfi^ing a definite 
series of applications according to schedule. 
The South Carolina A-^ricultural Experiment Station (^]^^) reported 
that insecticide tests were continued during 1937 t)ut nothing developed 
to indicate that changes are desirable in .the 193^ recommendations, i.e., 
5 percent of roteno.".e used as a spray at thp rate of 3 pounds to 100 
gallons of vrater, or 5 percent of rotenone used as a dust diluted with 
talc or inert cln.y at the ro.te of 15 pounds to 85 pounds of the diluent. 
