Published online by Cambridge University Press: 12 June 2017
In 1983 and 1984, 20 commercial soybean [Glycine max (L.) Merr.] cultivars were field tested for their response to fluchloralin [N-(2-chloroethyl)-2,6-dinitro-N-propyl-4-(trifluoromethyl)benzenamine], metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-l,2,4-triazin-5(4H)-one], and vernoiate [S-propyl dipropylcarbamothioate]. Recommended rates for the herbicides were 1.1, 0.4, and 2.8 kg ai/ha, respectively. Each herbicide was applied at recommended (lx), 2x, and 4x rates in both years with an 8x rate added in 1984. Plant height, vigor, and injury were used to determine herbicide effects. Differences existed among cultivars, herbicides, and rates. Increased herbicide rates generally resulted in reduced plant height and vigor and increased plant injury. Cultivars tolerant to the three herbicides included Cumberland, Essex, FFR 560, NAPB 420, and Pixie.