Evaluating a premix of glufosinate/quizalofop (Zalo ^® ) for control of volunteer corn in corn resistant to aryloxyphenoxypropionates

Abstract

Nebraska has significant acreage under a continuous corn production system each year, in which managing volunteer corn remains a persistent challenge for growers. A new premix of glufosinate/quizalofop (Zalo ^® ) was recently registered for weed control in glufosinate-resistant canola, cotton, and soybean. The objectives of this study were to (1) compare glufosinate/quizalofop (Zalo ^® ) with quizalofop (Assure ^® II) applied at V3 or V6 growth stages for control of glufosinate/glyphosate-resistant volunteer corn in corn resistant to aryloxyphenoxypropionates ( Enlist ^® corn), and (2) evaluate interactions with 2,4-D and their effects on volunteer corn density, biomass, and corn yield. Field experiments were conducted in 2023 and 2024 near Clay Center, NE (three site-years) and in 2024 near Rosemount, MN (one site-year). Glufosinate/quizalofop applied at 706 or 948 g ai ha ^–1 provided 98% to 99% control of volunteer corn, as well as reductions in density and biomass 28 days after application (DAA), regardless of volunteer corn planting density and corn growth stage at herbicide application, and these outcomes were comparable to quizalofop applied at 65 or 86 g ai ha ^–1 . When the lower rate of glufosinate/quizalofop (706 g ai ha ^–1 ) was mixed with 2,4-D (1,064 g ae ha ^–1 ), volunteer corn control ranged from 84% to 92% at 14 DAA across two site-years. Volunteer corn control improved to ≥ 96% by 28 DAA or when the higher rate of glufosinate/quizalofop (948 g ai ha ^–1 ) was mixed with 2,4-D 14 DAA. Enlist corn yield increased in the plots sprayed with herbicides compared with the nontreated control, with no difference among herbicide programs and it was comparable to the weed-free treatment. The results of this study indicate that glufosinate/quizalofop could provide an effective postemergence herbicide option for managing glufosinate/glyphosate-resistant volunteer corn, pending registration for use in Enlist ^® corn.