Herbicide safener increases weed-management tools for control of annual grasses in wheat

Abstract

Annual grass weeds reduce profits of wheat farmers in the Pacific Northwest. The very-long-chain fatty acid elongase (VLCFA)-inhibiting herbicides S-metolachlor and dimethenamid-P could expand options for control of annual grasses, but are not registered in wheat due to crop injury. Our studies evaluated a safener, fluxofenim, applied to wheat seed for protection of nineteen soft white winter wheat varieties from S-metolachlor, dimethenamid-P and pyroxasulfone herbicides, investigated the response of six varieties (UI Sparrow, LWW 15-72223, UI Magic CL+, Brundage 96, UI Castle CL+ and UI Palouse CL+) to incremental doses of fluxofenim, established fluxofenim dose required to optimally protect the varieties from VLCFA-inhibiting herbicides, and assessed the impact of fluxofenim dose on glutathione S-transferase (GST) activity in three wheat varieties (UI Sparrow, Brundage 96 and UI Castle CL+). Fluxofenim increased the biomass of four varieties treated with S-metolachlor or dimethenamid-P herbicides and one variety treated with pyroxasulfone. Three varieties showed tolerance to the herbicides regardless of the fluxofenim treatment. Estimated fluxofenim doses resulting in 10% biomass reduction of wheat ranged from 0.55 g ai kg-1 seed to 1.23 g ai kg-1 seed. Fluxofenim doses resulting in 90% increased biomass to S-metolachlor, dimethenamid-P, and pyroxasulfone ranged from 0.07 to 0.55, 0.09 to 0.73, and 0.30 to 1.03 g ai kg-1 seed, respectively. Fluxofenim at 0.36 g ai kg-1 seed increased GST activity in UI Castle CL+, UI Sparrow and Brundage 96 by 58%, 30% and 38%, respectively. These results suggest that fluxofenim would not damage wheat seedlings up to 3x the rate labeled for sorghum, and fluxofenim protects soft white winter wheat varieties from S-metolachlor, dimethenamid-P or pyroxasulfone injury at the herbicide rates evaluated.

The safener isoxadifen‐ethyl confers fenoxaprop‐p‐ethyl resistance on a biotype of Echinochloa crus‐galli

“…Safeners are an important strategy to improve the diversity of herbicide mechanisms of action, resulting in more options for weed control and herbicide resistance management. 13 The safener isoxadifenethyl improves the selectivity of the herbicide fenoxaprop-p-ethyl in rice and provides greater control of Echinochloa sp. 14,15 The selectivity of fenoxaprop-p-ethyl on wheat is also improved with the presence of the safener mefenpyr-diethyl.…”

“…To improve herbicide selectivity, safeners are used in mixtures with the herbicide active ingredient or separately applied in the crop seeds. Safeners are an important strategy to improve the diversity of herbicide mechanisms of action, resulting in more options for weed control and herbicide resistance management 13 . The safener isoxadifen‐ethyl improves the selectivity of the herbicide fenoxaprop‐ p ‐ethyl in rice and provides greater control of Echinochloa sp 14,15 .…”

Herbicide safener increases weed-management tools for control of annual grasses in wheat – ERRATUM

“…Herbicide safener increases weed-management tools for control of annual grasses in wheat -ERRATUM In the original publication of this article (Raiyemo et al 2021), the associate editor was incorrectly identified. The associate editor for this article was Drew Lyon, Washington State University.…”

“…In the original publication of this article (Raiyemo et al 2021), the associate editor was incorrectly identified. The associate editor for this article was Drew Lyon, Washington State University.…”