Economic analysis of diversified corn herbicide programs for weed management and rotation flexibility in western Nebraska

Abstract Corn ( Zea mays L.), dry edible bean ( Phaseolus vulgaris L.), and sugarbeet ( Beta vulgaris L.) are frequently grown in rotation in the Panhandle of Nebraska. The primary weed challenges in this system are Palmer amaranth ( Amaranthus palmeri S. Watson) and kochia [ Bassia scoparia (L.) A. J Scott] with resistance to acetolactate synthase and 5‐enolpyruvylshikimate‐3‐phosphate synthase inhibitors. While effective herbicide options for managing these resistant weeds are limited in dry edible bean and sugarbeet, a broader range of herbicides are available in corn. A field experiment was conducted in 2022, 2023, and 2024 at the University of Nebraska‐Lincoln Panhandle Research and Extension Center near Scottsbluff, NE, to evaluate herbicide efficacy in corn and assess cost‐effectiveness of herbicide programs compatible with sugarbeet and dry edible bean rotation. Results indicated that the addition of a very long‐chain fatty acid (VLCFA)‐inhibiting herbicide to glyphosate (1260 g ae ha −1 ) + dicamba (279 g ae ha −1 ) provided comparable corn yields and weed control to more expensive herbicide programs. However, this combination may increase selection pressure for VLCFA‐inhibiting herbicide resistance since glyphosate and dicamba resistance are already common. Programs that included additional mechanisms of action (inhibitors of photosynthesis II‐, protoporphyrinogen oxidase‐, synthetic auxins‐, and 4‐hydroxyphenyl‐pyruvatedioxygenase) did not significantly improve weed control but incurred additional cost of $89–$120 ha −1 . Despite the added expense, such programs may be valuable for mitigating the spread of herbicide resistant weeds.