Interaction of quizalofop-p-ethyl with 2,4-D choline and/or glufosinate for control of volunteer corn in corn resistant to aryloxyphenoxypropionates

Authors

Mandeep Singh, University of Nebraska-LincolnFollow
Vipan Kumar, Cornell University
Stevan Z. Knezevic, University of Nebraska at LincolnFollow
Suat Irmak, The Pennsylvania State University
John L. Lindquist, University of Nebraska-LincolnFollow
Santosh Pitla, University of Nebraska-LincolnFollow
Amit J. Jhala, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

2023

Citation

DOI: 10.1017/wet.2023.79

Comments

This is a “preproof” accepted article for Weed Science. This version may be subject to change in the production process, and does not include access to supplementary material

Abstract

Corn resistant to aryloxyphenoxypropionates (FOPs) (Enlist™ corn) enables the use of quizalofop-p-ethyl (QPE) as a selective postemergence (POST) herbicide for control of glufosinate/glyphosate-resistant corn volunteers. Growers usually mix QPE with 2,4-D choline and/or glufosinate to achieve broad-spectrum weed control in Enlist™ corn. The objectives of this study were to (1) evaluate the efficacy of QPE applied alone or mixed with 2,4-D choline and/or glufosinate for control of glufosinate/glyphosate-resistant corn volunteers in Enlist™ corn and (2) determine the impact of application time (V3 or V6 growth stage of volunteer corn) of QPE-based treatments on volunteer corn control as well as Enlist™ corn injury and yield. Field experiments were conducted at South Central Agricultural Lab, Clay Center, NE in 2021 and 2022. Quizalofop-p-ethyl (46 or 93 g ai ha^‒1 ) applied at V3 or V6 growth stage controlled volunteer corn ≥ 88% and ≥ 95% at 14 and 28 d after treatment (DAT), respectively. The QPE (46 g ai ha^‒1 ) mixed with 2,4-D choline (800 g ae ha^‒1 ) had 33% less expected control of V3 volunteer corn in 2021, and 8% less than expected control of V6 volunteer corn in 2022 at 14 DAT. Volunteer corn control was improved by 7%-9% using the higher rate of QPE (93 g ai ha^‒1 ) in a mixture with 2,4-D choline (1,060 g ae ha^‒1 ). The QPE mixed with glufosinate had an additive effect and interactions in any combinations were additive beyond 28 DAT. Mixing 2,4-D choline can reduce QPE efficacy on glufosinate/glyphosate-resistant corn volunteers up to 14 DAT when applied at the V3 or V6 growth stage; however, the antagonistic interaction did not translate into corn yield loss. Increasing the rate of QPE (93 g ai ha^‒1 ) while mixing with 2,4-D choline can reduce antagonism.