Studies were conducted in 1999, 2000, and 2001 to evaluate broadleaf weed control in cotton with postemergence applications of bromoxynil and bromoxynil plus CGA 362622. Bromoxynil was applied at 280 and 560 g ai/ha, and CGA 362622 was applied at 0, 3.8, and 7.5 g ai/ha in a factorial treatment arrangement. Cotton injury 7 d after treatment (DAT) during the 3 yr was 11 to 35% with the herbicide mixtures, but injury did not exceed 2% 28 DAT when averaged over years. CGA 362622 plus bromoxynil controlled velvetleaf, smooth pigweed, common ragweed, and common cocklebur at least 77% 28 DAT. Control of morningglory species was at least 87% with herbicide combinations, except in 2001 when control was only 60% with 280 g/ha bromoxynil plus 3.8 g/ha CGA 362622. Bromoxynil also controlled jimsonweed, but CGA 362622 did not. Spurred anoda control pooled over years did not exceed 53% with bromoxynil or bromoxynil plus CGA 362622 mixtures. Cotton yields generally reflected the level of weed control from the herbicide treatments. In these studies, mixtures of CGA 362622 with bromoxynil controlled several broadleaf weeds better than did either herbicide alone.
Nomenclature: Bromoxynil; CGA 362622 (proposed common name trifloxysulfuron sodium), N-[(4,6-dimethoxy-2-pyrimidinyl)carbamoyl]-3-(2,2,2-trifluoroethoxy)-pyridin-2-sulfonamide sodium salt; annual morningglory species, Ipomoea spp.; common cocklebur, Xanthium strumarium L. #3 XANST; common ragweed, Ambrosia artemisiifolia L. # AMBEL; jimsonweed, Datura stramonium L. # DATST; smooth pigweed, Amaranthus hybridus L. # AMACH; spurred anoda, Anoda cristata (L.) Schlecht. # ANVCR; velvetleaf, Abutilon theophrasti Medicus # ABUTH; cotton, Gossypium hirsutum L.
Additional index words: IPOHE, IPOLA, Ipomoea hederacea (L.) Jacq., Ipomoea lacunosa L., Ipomoea purpurea (L.) Roth, IPOPU, ivyleaf morningglory, pitted morningglory, tall morningglory.
Abbreviations: DAT, days after treatment; POSD, postdirected; POST, postemergence; PRE, preemergence.
