Abstract Glufosinate is a key postemergence (POST) herbicide in U.S. soybean production, particularly where resistance to glyphosate and acetolactate synthase (ALS) inhibitors is widespread. A 25-question survey of soybean growers, agronomists, and industry professionals in Arkansas and Wisconsin was conducted in the Fall of 2022 to characterize glufosinate use patterns, weed management challenges, and stakeholder perceptions. Palmer amaranth was reported as the most problematic weed in Arkansas (97% of respondents), and waterhemp was most frequently reported in Wisconsin (92%). Suspected glyphosate resistance was widely reported (97% Arkansas; 88% Wisconsin), and suspected glufosinate resistance was reported by 37% of Arkansas respondents and 3% of Wisconsin respondents. Glufosinate was integrated into weed management programs by 84% of Arkansas respondents and 53% of Wisconsin respondents, and most applications targeted broadleaf weeds ≤15 cm tall. Carrier volume selections included 103–140 L ha −1 (75%; Arkansas) and 150–187 L ha −1 (86%; Wisconsin). Arkansas respondents most frequently reported using glufosinate in a sequential first and second POST program (62%). In Wisconsin, glufosinate use was most reported only in the first POST application (37%), followed closely by sequential use in the first and second POST applications (34%). Weed size, followed by carrier volume and air temperature, were ranked as the most important factors affecting glufosinate performance. Ammonium sulfate was the most used adjuvant (45% Arkansas; 67% Wisconsin), and spray water quality was rarely tested. Frequently reported tank-mix partners included glyphosate and PPO inhibitors in Arkansas and synthetic auxins and clethodim in Wisconsin. Extension efforts should emphasize applying glufosinate to small weeds (<10 cm in height), optimizing application technology and spray solution characteristics (nozzle, carrier volume, water quality/adjuvant selection), and spraying under favorable environmental conditions. Improving application consistency can reduce weed escapes and repeat POST applications, lowering selection pressure and preserving glufosinate as an important POST option.
Arsenijević et al. (Thu,) studied this question.