Research was conducted along the Texas Gulf Coast in 1998 and 1999 to determine trifloxysulfuron soil persistence and potential injury to corn, grain sorghum, rice, and soybeans. Trifloxysulfuron was applied at 0, 7.5, and 60 g/ha to plots 0, 15, 30, 60, and 90 d prior to planting of crops. Corn and grain sorghum were more sensitive to trifloxysulfuron than rice and soybeans when planted 0 to 90 d after treatment (DAT). Trifloxysulfuron was more persistent at the San Patricio location than at Fort Bend, which had a lower soil pH. However, no phytotoxicity or plant-height reduction was observed at the four locations with corn, grain sorghum, rice, and soybeans planted 209 to 312 DAT. Greenhouse data showed that neither corn nor sunflower planted 209 to 312 DAT were adversely affected by either rate of trifloxysulfuron. Trifloxysulfuron applied to cotton up to 20 g/ha the previous year should not cause phytotoxicity to corn, grain sorghum, rice, or soybeans when grown in rotation under soil and weather conditions similar to those in these studies.

Nomenclature: Trifloxysulfuron{N-[4,6-dimethoxy-2-pyrimidinyl carbamoyl]-3-(2,2,2-trifluoroethoxy)-pyridin-2-sulfonamide sodium salt}; cotton, Gossypium hirsutum L.; corn, Zea mays L. ‘N7639BT’; grain sorghum, Sorghum bicolor L. ‘KS735’; rice, Oryza sativa L. ‘Cypress’; soybeans, Glycine max L. ‘Delta and Pine Land 3571’