Abstract
Field studies were conducted in 1991 and 1992 to evaluate the response of soybean, red rice, and rice the following year to AC 263,222 applied alone and in tank mixtures with imazethapyr or imazaquin. In 1991, AC 263,222 applied alone at 18, 36, and 70 g ai ha-1 resulted in visual soybean injury that did not exeed 9, 19, and 35%, respectively. Adding imazethapyr at 36 g ha-1 or imazaquin at 70 g ha-1 to AC 263,222 in a tank mixture did not increase soybean injury over the individual rate of AC 263,222 applied alone. Soybean yields were not reduced by any treatment. AC 263,222 at rates of 14 g ha-1 or greater alone or in tank mixtures injured soybean 39% or greater in 1992. However, injury did not affect yield when compared to the untreated check. In one study, rice injury was observed the following year from AC 263,222 alone and in tank mixtures. Injury was dependent on AC 263,222 rate. The only treatments to reduce rice yields were AC 263,222 applied at 70 g ha-1 alone and at 36 g ha-1 in a tank mixture with imazethapyr at 36 g ha-1. At least 60% red rice control was observed from 18 g ha-' AC 263,222 combined with either 36 g ha-1 imazethapyr or 70 g ha-1 imazaquin. Red rice control increased as rate of each herbicide in the tank mixtures increased. Control was improved by applying these treatments to red rice plants no greater than 19 cm tall. Nomenclature: AC 263,222, [4,5-dihydro-4-methyl-4-(lmethylethyl)-5-oxo-IH -imidazol-2yl]-5-methyl-3pyridinecarboxylic acid); imazethapyr[4,5-dihydro-4-methyl-4(1-methylethyl)-5-oxo-lH -imidazole-2-yi]-5-ethyl-3pyridinecarboxylic acidl; imazaquin2-[4,5-dihydro-4-methyl-4-(l methylethyl)-5-oxo- 1 H -imidazole-2-yl]-3-quinolinecarboxylic acid); red rice, Oryza sativa L.; rice, Oryza saliva L. 'Millie' and 'Maybelle'; soybean, Glycine max (L.) Merr. rtracy M'.
Grymes, Charles Frost (1993). AC 263,222 for red rice control in soybeans and its potential injury to rice in a rotation. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1993 -THESIS -G894.