Tolerance of White Bean to Tiafenacil Herbicide Mixtures and Control of Multiple Herbicide-Resistant Horseweed With Tiafenacil Herbicide Mixtures

Abstract

There is limited information on the tolerance of white bean to tiafenacil herbicide mixtures applied preplant (PP) and the efficacy of tiafenacil herbicide mixtures applied PP to control multiple herbicide-resistant (MHR) horseweed. The objective aim of this research was to ascertain the tolerance of white beans to tiafenacil herbicide mixtures and determine if MHR horseweed control with tiafenacil can be improved by adding herbicide partners in a surrogate soybean crop. During 2021 and 2022 four experiments were performed to determine the tolerance of white bean to tiafenacil herbicide mixtures and five experiments were conducted to determine MHR horseweed control with tiafenacil mixtures in ON, Canada. All tiafenacil mixtures evaluated except those that included 2,4-D ester caused minimal (≤ 4%) white bean injury and had no adverse effect on white bean stand, dry biomass, height, maturity (as measured by seed moisture (SM) content at harvest), or yield. Glyphosate + tiafenacil + 2,4-D ester and glyphosate + tiafenacil + bromoxynil + 2,4-D ester caused up to 8% white bean injury but had no adverse effect on white bean stand, dry biomass, height, maturity, or yield. Glyphosate + tiafenacil or co-applied with bromoxynil, metribuzin, or 2,4-D controlled MHR horseweed 23-75%, reduced density up to 62% and reduced biomass up to 56%; consequently, horseweed interference with these tiafenacil mixtures resulted in soybean yield comparable to the non-treated (weedy) control. Glyphosate + tiafenacil + halauxifen-methyl and the co-application of glyphosate + tiafenacil + bromoxynil with metribuzin, halauxifen-methyl, or 2,4-D ester controlled MHR horseweed 73-94%, reduced density up to 79%, and reduced biomass up to 86%. Reduced MHR horseweed interference with the aforementioned tiafenacil mixtures resulted in soybean yield comparable to the weed-free control. In conclusion, all tiafenacil mixtures evaluated except those that contained 2,4-D ester can be safely used in white bean. Glyphosate + tiafenacil + halauxifen-methyl and the co-application of glyphosate + tiafenacil + bromoxynil with metribuzin, halauxifen-methyl, or 2,4-D ester provided the most consistent control of MHR horseweed.

Sensitivity of Azuki Bean and Control of Multiple Herbicide-Resistant Canada Fleabane With Saflufenacil Herbicide Mixtures

“…Results are similar to other studies that have shown little injury in soybean or other market classes of dry bean with PP application of glyphosate + saflufenacil co-applied with metribuzin, bromoxynil, halauxifen-methyl or 2,4-D ester (Budd et al, 2016a(Budd et al, , 2016bMiller et al, 2012;Westerveld et al, 2021). In other studies, MHR Canada fleabane interference caused a soybean yield decrease of 41% (Soltani et al, 2023), 67% (Westerveld et al, 2021), 73% (Budd et al, 2016a), and 82% (Eubank et al, 2008). Furthermore, reduced MHR Canada fleabane interference with glyphosate + saflufenacil co-applied with metribuzin or 2,4-D ester resulted in soybean yield that was similar to the weed-free control (Budd et al, 2016a(Budd et al, , 2016b.…”

“…Effect of preplant glyphosate + saflufenacil herbicide mixtures on visible percent control, density and dry biomass of multiple herbicide-resistant Canada fleabane (MHRCF), soybean injury and yield at sites near Bothwell, Moraviantown and Ridgetown, ON in 2021 (n = 3) and 2022 (n = 2). Means followed by the same letter within a column are not significantly different according to a Tukey-Kramer multiple range test at P < 0.05 a (Soltani et al, 2023). However, glyphosate + tiafenacil + bromoxynil tankmixes with metribuzin, halauxifen-methyl, or 2,4-D ester controlled MHR Canada fleabane 79, 76, and 78%, respectively (Soltani et al, 2023).…”

“…Means followed by the same letter within a column are not significantly different according to a Tukey-Kramer multiple range test at P < 0.05 a (Soltani et al, 2023). However, glyphosate + tiafenacil + bromoxynil tankmixes with metribuzin, halauxifen-methyl, or 2,4-D ester controlled MHR Canada fleabane 79, 76, and 78%, respectively (Soltani et al, 2023).…”