Response of Eight Market Classes of Dry Bean (Phaseolus vulgaris L.) to Pendimethalin

There is little information on the tolerance of dry bean to pendimethalin. Field studies were conducted in 2007 to 2009 at Exeter, Ontario and in 2008 and 2009 at Ridgetown, Ontario to evaluate tolerance of black, cranberry, kidney, otebo, pink, pinto, Small Red Mexican and white bean to the pendimethalin applied preplant incorporated at 1080 and 2160 g.a.i.ha-1. Pendimethalin PPI caused minimal injury in most market classes of dry bean at 1 and 2 WAE. There was no injury in various market classes of dry bean with the low dose at 1 and 2 weeks after emergence (WAE). However, at the high dose there was 0 to 4% injury at 1 WAE and 0 to 7% injury at 2 WAE in black, cranberry, kidney, otebo, pink, pinto, SRM and white bean. Pendimethalin PPI was more injurious in white bean than in black, cranberry, kidney, otebo, pink, pinto and SRM bean. Pink and SRM bean exhibited the most tolerance to pendimethalin applied PPI at 1080 g.ai.ha-1 or 2160 g.ai.ha-1. Pendimethalin caused no adverse effect on plant height, shoot dry weight, seed moisture content and seed yield of black, cranberry, kidney, otebo, pink, pinto, SRM and white bean. Based on these results, there is an adequate margin of crop safety for pendimethalin applied PPI at the proposed dose of 1080 g.ai.ha-1 in black, cranberry, kidney, otebo, pink, pinto, SRM and white bean in Ontario.