Tobacco Budworm, Bollworm, and Boll Weevil: Effectiveness of Newly Developed Experimental Insecticides on Cotton in the Southeast.1234

Abstract

In replicated field tests permethrin (FMC-33297) (3-(phenoxyphenyl) methyl cis, trans- (±)-3-(2,2-dichloroethenyl),-2,2-dimethylcyclopane-carboxylate. Shell SD-43775 (cyano (3-phenoxyphenyl) methyl 4-chloro-alpha-(1-methylethyl) (benzeneacetate), and Shell SD-41706 (cyano (3-phenoxy-phenyl) methyl 2,2,3,3-tetramethylcyclopropane-carboxylate) gave outstanding control of the boll weevil, Anthonomus grandis Boheman, and the bollworm complex. Heliothis zea (Boddie) and H. virescens (F.). Bay NTN-9306 (O-ethyl[4-methylthio) phenyl]S-propyl phosphorodithioate) plus azinphosmethyl gave control equal to or better than the treated control, toxaphene + methyl parathion + chlordimeform. Rohm and Haas RH-218 (O-ethyl S-propyl O-2,4.6-trichlorophenyl) phosphorothioate) + toxaphene gave better control of Heliothis spp. than the treated control but produced low yields and was phytotoxic. In all tests, correlation analysis showed that the means for boll weevil and Heliothis spp. infestation were negatively correlated with yield, and the highest yields were obtained when boll weevil infestations were held below the economic threshold level (10%) and when Heliothis spp. larval infestations in squares did not exceed 1.17±0.17 SE larvae/100 squares. Numbers of live Heliothis spp. larvae/100 squares can be used readily to determine a treatment schedule that will give a sound pest management program.