Antagonistic effect of MCPA on Avena sterilis with tralkoxydim

Abstract

Control of wild oats (Avena sterilis ssp. ludoviciana Nyman) with tralkoxydim {2-[1-(ethoxyimino)propyl]-3- hydroxy-5-(2,4,6-trimethylphenyl) cyclohex-2-enone} in a tank mix with MCPA (2-methyl-4-chloro phenoxy acetic acid) and/or bromoxynil (3,5-dibromo-4-hydroxybenzonitrile-octanoate and heptanoate esters) was determined under controlled conditions. Tralkoxydim alone and combinations with bromoxynil and MCPA were applied at different rates and growth stages of wild oats. Fresh leaf mass was determined at various intervals. Growth control of wild oats was significantly reduced by as much as 21% by the addition of MCPA at the lower rates of tralkoxydim. Antagonism occurred at both application stages and was first detected 7 days after herbicide application. Addition of bromoxynil did not reduce the effect of tralkoxydim drastically. The tralkoxydim alone and the combination of tralkoxydim plus bromoxynil plus MCPA controlled wild oats satisfactorily.