Influence of bromoxynil on annual grass control by graminicides

Greenhouse experiments were conducted to determine the effect of mixing bromoxynil with clethodim, sethoxydim, fluazifop-P, fluazifop-P plus fenoxaprop-P, or quizalofop-P on annual grass control. Antagonism with mixtures of bromoxynil and graminicides was dependent upon species and the graminicide in the mixture. Goosegrass control was unaffected by mixing bromoxynil with any graminicide. Mixing bromoxynil with clethodim, sethoxydim, fluazifop-P, or fluazifop-P plus fenoxaprop-P had no effect on control of Texas panicum, but the rate of quizalofop-P required for 80% control was increased 240%. Mixing bromoxynil with clethodim or sethoxydim had no effect on control of large crabgrass or yellow foxtail, but the rate of fluazifop-P, fluazifop-P plus fenoxaprop-P, or quizalofop-P required for 80% control was increased 180 to 290%. Antagonism of large crabgrass and yellow foxtail control with mixtures of quizalofop-P and bromoxynil increased as the rate of bromoxynil increased. Antagonism toward large crabgrass and yellow foxtail was alleviated by applying bromoxynil 6 d before the graminicides or 3 or 6 d after the graminicides.