Abstract

Five field experiments were conducted in Ontario to determine the tolerance of dry beans to pyraflufen-ethyl (6.7 and 13.4 g ai ha^-1), 2,4-D ester (520.3 and 1040.6 g ai ha^-1) and pyraflufen-ethyl/2,4-D ester (527 and 1054 g ai ha^-1) applied preplant. Pyraflufen-ethyl at 6.7 and 13.4 g ai ha^-1 caused < 2% injury in azuki, kidney, small red, and white bean. 2,4-D ester at 520.3 and 1040.6 g ai ha^-1 caused up to 4 and 6% injury in azuki bean; up to 5 and 12% injury in kidney bean; up to 7 and 12% injury in small red bean; and up to 5 and 8% injury in white bean, respectively. Pyraflufen-ethyl/2,4-D ester at 527 and 1054 g ai ha^-1 caused up to 4 and 6% injury in azuki bean; 5 and 11% injury in kidney bean; 7 and 13% injury in small red bean; and 5 and 10% injury in white bean, respectively. Pyraflufen-ethyl (6.7 and 13.4 g ai ha^-1), 2,4-D ester (520.3 and 1040.6 g ai ha^-1) or their combination applied preplant caused no adverse effect on dry bean stand, aboveground dry biomass, height, seed moisture content, or yield except for 2,4-D (2X rate) and pyraflufen-ethyl/2,4-D ester (2X rate) which reduced dry bean aboveground biomass as much as 32% and plant height up to 28%. This study concludes that pyraflufen-ethyl (6.7 g ai ha^-1), 2,4-D ester (520.3 g ai ha^-1), and pyraflufen-ethyl/2,4-D ester (527 g ai ha^-1) applied preplant is safe to use for weed management in azuki, kidney, small red, and white bean. However, care must be taken to avoid spray overlaps with 2,4-D ester and pyraflufen-ethyl/2,4-D ester to avoid unacceptable dry bean injury.

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