Herbicidal control of triazine-resistant (TR) kochia was evaluated in
no-till grain sorghum. Herbicides were applied early preplant (EPP) or
POST. In EPP experiments, herbicides plus nonionic surfactant at 0.25
% v/v were applied 7, 2, or 0 wk before planting (WBP). Fluorochlorido
ne at 0.8 kg ai/ha applied 7 or 2 WBP, pyridate at 1.0 kg ai/ha applie
d 2 WBP, and paraquat at 0.4 kg ai/ha applied 0 WBP controlled 94 to 9
9% of TR kochia; a prepackaged mixture of glyphosate plus 2,4-D at 0.3
plus 0.6 kg ae/ha and paraquat at 0.4 kg/ha applied 7 or 2 WBP contro
lled 71 to 82% of TR kochia; and 2,4-D ester at 0.6 kg ae/ha applied 2
WBP controlled 75% of TR kochia. Linuron at 0.8 kg ai/ha and atrazine
at 2.2 kg ai/ha were ineffective. In the POST herbicide experiments,
where paraquat plus metolachlor at 0.6 plus 1.7 kg ai/ha were applied
17 d before planting, various combinations and rates of bentazon plus
atrazine, bromoxynil, and dicamba with adjuvants provided good control
of TR kochia that was less than 8 cm tall.