Desiccation in dry edible beans with various herbicides

There is little information available on the effect of diquat, carfentrazone-ethyl, glufosinate ammonium, flumioxazin and saflufenacil applied alone or in tankmix combination with glyphosate as harvest aids in dry bean production under environmental conditions of the various production regions in Canada. A total of 11 field trials were conducted over a 3-yr period (2010, 2011, 2012) at Exeter, Ontario, Carman, Manitoba, and Lethbridge, Alberta, to evaluate various harvest-aid herbicides in dry bean. Comparison of leaf, pod and stem visual dry down at 4 and 8 d after desiccation application (DAA) indicated that adding a tankmix partner to glyphosate increased visual dry down of leaf, pod and stem 17, 10 and 15% at 4 DAA and 20, 17 and 14% at 8 DAA, respectively. At 8 DAA, glyphosate (450 or 900 g a.e. ha(-1)), diquat, glufosinate ammonium, carfentrazone-ethyl, flumioxazin and saflufenacil provided 13-58, 65-80, 64-71, 12-34, 36-52 and 41-73% dry down of the dominant weeds (AMARE, AMBEL, CHEAL and SETVI), respectively. Diquat, glufosinate ammonium, carfentrazone-ethyl, flumioxazin and saflufenacil tankmixed with glyphosate (450 or 900 g a.e. ha(-1)) provided 67-77, 65-71, 22-62, 45-69 and 44-74% weed dry down, respectively. Dry bean yield was not reduced with any of the desiccation treatments. Among desiccant treatments that provided consistent desiccation of dry bean and weeds, saflufenacil had the least environmental impact followed by flumioxazin, glufosinate ammonium and then diquat. Based on this study, diquat, glufosinate ammonium, flumioxazin and saflufenacil alone or in combination with glyphosate (450 or 900 g a.e. ha(-1)) provide consistent desiccation of weeds and dry bean.