Suppression of Pea(Pisum sativum)Root Rot by Dinitroaniline Herbicides

Abstract

Nine substituted dinitronaline herbicides were studied to determine their effectiveness in controlling common root rot of peas (Pisum sativum L.) caused by Aphanomyces euteiches Drechs. under field conditions. Most of the dinitroaniline herbicide treatments increased plant stand, plant fresh weight, and shelled pea yield due to root rot suppression in each of the three years studied. Weed control was good in all plots and did not contribute to yield differences. Root rot suppression and crop injury were the primary determinants of yields. The greatest yield increases when compared with the weeded control were 82% for 0.56 kg/ha of dinitramine (N 4,N 4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine) in 1974, 80% for 0.84 kg/ha of fluchloralin [N-(2-chloroethyl)-2,6-dinitro-N-propyl-4-(trifluoromethyl) aniline] in 1975, and 26% for 1.68 kg/ha of pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine] in 1976. The best average yield increases over all years were 54% for the combination of trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) and oryzalin (3,5-dinitro-N 4,N 4-dipropylsulfanilamide) at 0.56 + 0.56 kg/ha, 49% for fluchloralin at 0.84 kg/ha, and 43% for pendimethalin at 0.84 kg/ha. Annual applications of 0.84 kg/ha of trifluralin delayed the rate of pathogen infestation of a field repeatedly planted to peas.