Peanut response to delayed applications of fluridone and trifludimoxazin

Abstract The limited number of herbicides for use in peanut makes it difficult to diversify modes of action to combat advantageous weed species with reports of increasing herbicidal resistance. It is critically necessary to explore both new and repurposed chemistries with different modes of action for potential use on peanut crops. Little research has investigated peanut response to scenarios in which preemergence applications of fluridone or trifludimoxazin are delayed. Replicated field trials using small plots were conducted at the University of Georgia from 2022 to 2024 to identify any deleterious effects of fluridone applied at 126 g ai ha −1 or trifludimoxazin applied at 37 g ai ha −1 1, 3, 5, or 7 d after planting (DAP). The peanut population was not affected, regardless of herbicide or application timing. At 13 DAT, plant growth was reduced by 5% to 9% when fluridone had been applied 1, 3, 5, and 7 DAP. Visual crop growth was reduced by 10% to 19% with applications of trifludimoxazin, with the greatest effect occurring when it was applied at 7 DAP. Trifludimoxazin also caused 7% foliar leaf necrosis when averaged over application timings. Regardless of application timing, peanut height was reduced by both herbicides at 30 DAP but not at 80 DAP. However, at 80 DAP, plant width was reduced by 4% after fluridone and trifludimoxazin had been applied. Peanut yield was not affected by herbicide treatment regardless of when it was applied. Fluridone and trifludimoxazin applied as late as 7 DAP can injure peanut but not affect yield.