Cinmethylin for Weed Control in Soybeans,Glycine max

Abstract

A 3-yr study was conducted to evaluate efficacy and soybean tolerance of cinmethylin. Cinmethylin was applied preemergence alone at 0.6, 0.8, and 1.0 kg ai/ha or in combination with metribuzin at 0.3 kg/ha. These treatments did not injure soybeans in field trials in 1984, 1985, and 1986. The combination of cinmethylin at 0.7 kg/ha and metribuzin at 0.3 kg/ha controlled more than 90% of large crabgrass, fall panicum, and yellow foxtail. Redroot pigweed and common lambsquarters control was also excellent. Residual control of all grass species was excellent for 8 weeks after preemergence application, followed by reduced control in two of the three grasses. The combination of cinmethylin and metribuzin at 0.7 and 0.3 kg/ha, respectively, significantly increased soybean yields compared to those of untreated plots. These yields were comparable with those obtained from the combination of alachlor and metribuzin at 2.0 and 0.3 kg/ha, respectively. Cinmethylin treatments had no adverse effects on soybean yield components including pods/plant, seed/pod, and seed weight. Cinmethylin shows potential as a preemergence herbicide for full-season weed control in soybean production.