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Trifludimoxazin + saflufenacil is a premix protoporphyrinogen oxidase-inhibiting herbicide with both PRE and POST activity pending U.S. Environmental Protection Agency registration for burndown application ahead of planting corn, soybean, grain sorghum, and wheat. Early-season cotton emergence and growth often coincide in the Mid-South with preplant herbicide application in later planted soybean, thereby increasing opportunity for off-target herbicide movement from adjacent fields. Field studies were conducted in 2024 to identify any deleterious impacts of reduced rates of trifludimoxazin + saflufenacil (1/8-1/256x of the lowest proposed labeled application rate of 38.3 g ai ha-1) applied to one- to two-leaf cotton. Visual injury one week after treatment (WAT) with 1/8, 1/16, 1/32, and 1/64x rate of trifludimoxazin + saflufenacil was 93, 84, 66, and 40%, respectively; whereas at four WAT these respective rates resulted in visual injury of 55, 30, 11, and 4%. Trifludimoxazin + saflufenacil at these rates reduced cotton height 30 to 72% and 21 to 60%, two and four WAT, respectively, and reduced seed cotton yield 64, 26, 6, and 1%. Application of trifludimoxazin + saflufenacil directly adjacent to cotton in early vegetative growth should be avoided as severe visual injury will occur. In cases where off-target movement does occur, impacted cotton should not be expected to fully recover and negative impact on growth and yield will be observed at the three highest reduced rates evaluated.
