Sensitivity of nonresistant winter wheat to quizalofop-P-ethyl in central Oklahoma and Kansas

Abstract The CoAXium ® Production System includes a new herbicide-resistant wheat (AXigen ) that allows for fall and/or spring postemergence (POST) applications of quizalofop-P-ethyl (QPE) control winter annual grass weeds. As area planted with AXigen increases, so will the use QPE herbicide, and this comes an increased chance physical drift, tank contamination, or misapplication to nearby sensitive plants. A total eight field studies were conducted at four locations during 2018–2019 2019–2020 growing seasons understand response nonresistant when exposed various rates herbicide. Five evaluated: 1× (92 g ai ha −1 ), 1/10×, 1/50×, 1/100×, 1/200×. Treatments applied in (2- 3-leaf wheat) (3- 4-tiller wheat). Results indicated interaction between application timing rate on grain yield half site-years. resulted complete near loss regardless timing. However, 1/10× ranging from 0% 41% fall-applied, whereas 80% 100% loss. For site-years only main effect was significant, 86% observed following exposure rates. all site-years, it infrequent significant reductions three lowest QPE. If two highest considered represent contamination we can assume drift non-AXigen is not major concern if proper guidelines are followed. Conversely, should be carefully by growers who have both varieties.