Weed Control in Cotton (Gossypium hirsutum) with Postemergence Applications of Trifloxysulfuron-sodium

Abstract

Experiments were conducted in Florida from 1998 through 2000 to evaluate trifloxysulfuron-sodium applied POST for weed control in cotton. The addition of 0.25% (v/v) nonionic surfactant (NIS) to trifloxysulfuron-sodium, regardless of rate, increased sicklepod control 10 to 50% 6 and 19 wk after planting (WAP). All trifloxysulfuron-sodium treatments controlled Florida beggarweed and redweed 70 to 100% 6 and 19 WAP. Pitted morningglory was controlled 68 to 100% by trifloxysulfuron-sodium treatments; however, control was higher for treatments that contained 0.25% v/v NIS. Trifloxysulfuron-sodium provided poor control of smallflower morningglory. A sequential application of fluometuron PRE followed by trifloxysulfuron-sodium POST provided better control of smallflower morningglory than trifloxysulfuron-sodium alone 19 WAP. Cotton treated with trifloxysulfuron-sodium yielded higher than the nontreated check and early POST treatments that included 0.25% v/v NIS yielded approximately 20% higher than non-NIS treatments. Trifloxysulfuron-sodium applied POST provided season-long control of Florida beggarweed, pitted morningglory, redweed, and sicklepod with the addition of 0.25% v/v NIS but did not control smallflower morningglory in cotton.