Field studies were conducted to evaluate weed control with combinations of glyphosate at 750 g ae/ha and the insecticides acephate (370 g ai/ha), dicrotophos (370 g ai/ha), dimethoate (220 g ai/ha), fipronil (56 g ai/ha), imidacloprid (53 g ai/ha), lambda-cyhalothrin (37 g ai/ha), oxamyl (280 g ai/ha), or endosulfan (420 g ai/ha) and insect control with coapplication of the herbicide with insecticides acephate, dicrotophos, dimethoate, and imidacloprid. Applying lambda-cyhalothrin or fipronil with glyphosate reduced control of hemp sesbania by 19 and 9 percentage points, respectively, compared with glyphosate alone. Acephate, dicrotophos, dimethoate, imidacloprid, lambda-cyhalothrin, oxamyl, and endosulfan did not affect hemp sesbania, pitted morningglory, prickly sida, and redweed control by glyphosate. Lambda-cyhalothrin and fipronil did not affect glyphosate control of weeds other than hemp sesbania. Addition of glyphosate to dicrotophos improved cotton aphid control 4 d after treatment compared with dicrotophos alone. Thrips control was improved with addition of glyphosate to imidacloprid. Insect control was not reduced by glyphosate regardless of insecticide.
Nomenclature: Acephate, O, S-dimethyl acetylphosphoramidothioate; dicrotophos, 3-dimethoxyphosphinoyloxy-N,N-dimethylisocrotonamide; dimethoate, O,O-dimethyl-S-methylcarbamoylmethyl phosphorodithioate; endosulfan, (1,4,5,6,7,7-hexachloro-8,9,10-trinorborn-5-en-2,3-ylenebismethylene)sulfite; fipronil, 5-amino-1-(2,6-dichloror-α,α,α-triflouro-p-tolyl)-4-trifluoromethylsulfinylpyrazole-3-carbonitrile; glyphosate; imidacloprid, (EZ)-1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine; lambda-cyhalothrin, reaction product comprising equal quantities of (S-α-cyano-3-phenoxybenzyl (Z)-(1R,3R)-3-(2-chloro-3,3,3-trifluoropropenyl)-2,2-dimethylcyclopropanecarboxylate and (R)-α-cyano-3-phenoxybenzyl (Z)-(1S,3S)-3-(2-chloro-3,3,3-trifluoropropenyl)-2,2-dimethylcyclopropanecarboxylate or of (S)-α-cyano-3-phenoxybenzyl (Z)-(1R)-cis-3-(2-chloro-3,3,3-trifluoropropenyl)-2,2-dimethylcyclopropanecarboxylate and (R)-α-cyano-3-phenoxybenzyl (Z)-(1S)-cis-3-(2-chloro-3,3,3-trifluoropropenyl)-2,2-dimethylcyclopropanecarboxylate; oxamyl, (EZ)-N,N-dimethyl-2-methylcarbamoyloxyimino-2-(methylthio)acetamide; hemp sesbania, Sesbania exaltata (Raf.) Rydb. ex A. W. Hill #3 SEBEX; AESVI; pitted morningglory, Ipomoea lacunosa L. # IPOLA; prickly sida, Sida spinosa L. # SIDSP; redweed, Melochoia corchorifolia L. # MEOCO; cotton, Gossypium hirsutum L; cotton aphids, Aphis gossypii Glover; thrips, Frankliniella spp.
Additional index words: Aphids, herbicide–insecticide combinations, pesticide compatibility, thrips.
Abbreviations: DAT, days after treatment; POST, postemergence.