CGA-362622 has been registered for postemergence (POST) over-the-top or POST-directed application in cotton. Research was conducted during 1998 in Texas to determine potential cotton phytotoxicity after POST application of CGA-362622 alone and with the insecticides acephate, dicrotophos, azinphos methyl, oxamyl, thiamethoxam, dimethoate, and malathion and to determine the response of four cotton cultivars to CGA-362622 applied alone. CGA-362622 applied with malathion injured cotton more than either pesticide applied alone, and yield was reduced in one of four locations when the pesticides were applied in mixture compared with nontreated cotton. Pyrithiobac or CGA-362622 mixed with malathion injured cotton similarly. The other insecticides tank mixed with CGA-362622 generally did not adversely affect cotton. The cotton cultivars ‘Delta and Pine Land 50’, ‘Paymaster 1220’, ‘Paymaster 1220RR’, and ‘Stoneville 474’ responded similarly to CGA-362622 applied alone or with insecticides.

Nomenclature: Acephate, O,S-dimethyl acetyl-phosphoramidothiate; azinphos methyl, {O,O-dimethyl S-[4-oxo-1,2,3-benzotriazin-3(4H)-yl methyl]phosphorodithioate}; CGA-362622; dicrotophos, dimethyl phosphate of 3-hydroxy-N,N-dimethyl-cis-crotonamide; dimethoate, [O,O-dimethyl S-(N-methylcarbamoylmethyl) phosporodithioate]; malathion, O,O-dimethyl phosphorodithiate of diethyl mercaptosuccinate; oxamyl, {methyl-N′N′-dimethyl-N-[(methyl carbamoxyl)oxy]-1-thiooxamimidate}; pyrithiobac; thiamethoxam, {4H-1,3,5-oxadiazin-4-imine, 3-[(2-chloro-5-thiazolyl)methyl]tetrahydro-5-methyl-N-nitro}; cotton, Gossypium hirsutum L. ‘Delta and Pine Land 50’, ‘Paymaster 1220’, ‘Paymaster 1220RR’, ‘Stoneville 474’.

Additional index words: Cotton injury, pesticide interaction, sulfonylurea herbicide.

Abbreviations: ALS, acetolactate synthase; DAP, days after planting; DAT, days after treatment; OT, over-the-top; POST, postemergence; PRE, preemergence.