The retention of the black color in canned black beans is viewed as a key attribute in finished product quality and is very important for consumer acceptance. Changes in production practices and black bean varieties may influence canned black bean quality. A field trial was conducted near Richville, Michigan in 2013 and 2014 to evaluate the effects of preharvest herbicide treatments on desiccation, yield, and black bean quality and color. The black bean varieties Zorro, Eclipse, and Zenith were planted on two different dates in each of two years. Three preharvest herbicide treatments, paraquat, glyphosate, and saflufenacil, were applied at two different application timings. Differences in black bean desiccation were greatest 3 DAT, with paraquat and saflufenacil showing the quickest desiccation. By 7 DAT, desiccation for most preharvest treatments was over 95%. Early applications of saflufenacil in the first planting had the greatest impact on yield for both years when compared with the nontreated control. Black bean color was lighter when glyphosate was applied early to Zenith and Zorro as assessed by a panel of over 20 evaluators. Lightness (L*) measurements also indicate lighter black bean color after canning with early applications of glyphosate. Eclipse had the lightest L* measurements while Zenith had the darkest, regardless of planting date or application timing. Overall, preharvest herbicides applied at the early application timing reduced black bean yield, with the largest reduction observed from applications of saflufenacil. The greatest loss of black color in canned beans was observed when glyphosate was applied at the early application timing; however, preharvest treatments applied at the standard timing very rarely impacted bean color.
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