Control of the Alfalfa Weevil, Hypera postica, in New York

Abstract

Experiments were conducted to determine the effectiveness of experimental, labeled, and mixtures of various insecticides for controlling the alfalfa weevil, Hypera postica (Gyllenhal), on fall, first-, and second-crop alfalfa. Fall-applied methoxychlor and a mixture of Guthion M-E® (O,O-diethyl S-(4-oxo-1,2,3-benzotriazin-3(4H)-yl-methyl) phosphorodithioate) and 3% Igepal CO-630® (nonylphenoxypoly(ethyleneoxy)ethanol 9–10 ethyleneoxy per mole of nonylphenol) did not give adequate control and both were below the normal performance of the standard fall-applied heptachlor. None of the stubble sprays, except HRS 1671 (heptachlorohexahydroketomethanophthalan), gave better control than lindane and few were more effective than the already recommended materials that were tested. Of the experimental insecticides tested, HRS 1671, Bayer 41831 (O,O-dimethyl O-(4-nitro-m-tolyl)phosphorothioate), AC 47031 (2-(diethoxyphosphinylimino)-1,3-dithiolane), AC47772 (2-(dimethoxyphosphinylimino)- 4-methyl-1,3-dithiolane), and R.P. 11974 (0,0-diethyl dithiophosphoryl methyl-3-chloro-6-benzoxazolone) showed the most promise.