Control of glyphosate/glufosinate-resistant volunteer corn in corn resistant to aryloxyphenoxypropionates

Abstract

Corn-on-corn production systems, common in highly productive irrigated fields in South Central Nebraska, can create issues with volunteer corn management in corn fields. EnlistTM corn is a new multiple herbicide–resistance trait providing resistance to 2,4-D, glyphosate, and the aryloxyphenoxypropionate herbicides (FOPs), commonly integrated in glufosinate-resistant germplasm. The objectives of this study were to (1) evaluate ACCase-inhibiting herbicides for glyphosate/glufosinate-resistant volunteer corn control in Enlist corn and (2) evaluate the effect of ACCase-inhibiting herbicide application timing (early POST vs. late POST) on volunteer corn control, Enlist corn injury, and yield. Field experiments were conducted in 2018 and 2019 at South Central Agricultural Laboratory near Clay Center, NE. Glyphosate/glufosinate-resistant corn harvested the year prior was cross-planted at 49,000 seeds ha–1 to mimic volunteer corn in this study. After 7 to 10 d had passed, Enlist corn was planted at 91,000 seeds ha–1. Application timing of FOPs (fluazifop, quizalofop, and fluazifop/fenoxaprop) had no effect on Enlist corn injury or yield, and provided 97% to 99% control of glyphosate/glufosinate-resistant volunteer corn at 28 d after treatment (DAT). Cyclohexanediones (clethodim and sethoxydim; DIMs) and phenylpyrazolin (pinoxaden; DEN) provided 84% to 98% and 65% to 71% control of volunteer corn at 28 DAT, respectively; however, the treatment resulted in 62% to 96% Enlist corn injury and 69% to 98% yield reduction. Orthogonal contrasts comparing early-POST (30-cm-tall volunteer corn) and late-POST (50-cm-tall volunteer corn) applications of FOPs were not significant for volunteer corn control, Enlist corn injury, and yield. Fluazifop, quizalofop, and fluazifop/fenoxaprop resulted in 94% to 99% control of glyphosate/glufosinate-resistant volunteer corn with no associated Enlist corn injury or yield loss; however, quizalofop is the only labeled product as of 2020 for control of volunteer corn in Enlist corn.

Interference and management of herbicide-resistant crop volunteers

“…Corn is grown in rotation with several crops, including cotton, sugarbeet, and soybean, with yield loss reported in the range of 4% to 83% depending on crop and density of volunteer corn (Chahal et al 2016;Rees and Jhala 2018). A monoculture of corn is a common practice among several growers in southcentral Nebraska that results in volunteer corn issue (Striegel et al 2020). Jeschke and Doerge ( 2008) reported 1.5% to 13% corn grain yield losses with volunteer corn density of 0.5 to 4 plants m −2 .…”

“…Volunteerism is a well-known phenomenon in agronomic crops, and in certain cases, presents a challenge for growers to find a selective herbicide for their management (Chahal and Jhala 2015). Herbicides commonly used for controlling weeds in rotational crops may not completely control herbicide-resistant (HR) crop volunteers, particularly in monoculture such as corn (Zea mays L.) after corn (Striegel et al 2020) or rice (Oryza sativa L.) after rice (Sanders et al 2020). Since the discovery of 2,4-D for broadleaf weed control in the early 1940s (Peterson et al 2016), several herbicides with distinct sites of action (SOAs) have been discovered and applied in a number of crops (Rüegg et al 2007); however, in recent years, the cost of discovery of a herbicide with a novel SOA that meets regulatory standards has increased significantly (Hall et al 2020).…”

“…While multiple HR crops have provided effective control of GR weeds, management of multiple HR crop volunteers is complicated for growers. For example, glufosinate/ glyphosate-resistant corn cannot be controlled with selective herbicides in corn (Striegel et al 2020). Imidazolinone-resistant (IR) barley (Hordeum vulgare L.), wheat (Triticum aestivum L.), or rice volunteers need alternate herbicides for their control in rotational crops (Burgos et al 2008).…”

“…In contrast, multiple HR crops have provided an opportunity to use a certain herbicide for control of crop volunteers. For instance, corn resistant to aryloxyphenoxypropionates (FOPs) provides an opportunity for selective control of glyphosate/glufosinate-resistant corn volunteers with quizalofop (Striegel et al 2020).…”

Sorption and desorption of bicyclopyrone on soils

“…Bicyclopyrone is typically used in mixtures and is marketed under the trade names of Talinor and Acuron (Syngenta) for the control of broadleaf and grass weeds in maize ( Zea mays L.), barley ( Hordeum vulgare L.), and wheat ( Triticum aestivum L.) crops. In particular, it is promoted for use against weeds that have developed resistance to glyphosate, acetolactate synthase (ALS) inhibitors, and auxinic herbicides (Benoit, Soltani, Hooker, Robinson, & Sikkema, 2019; Kumar, Liu, Boyer, & Stahlman, 2019; Sarangi & Jhala, 2017; Striegel et al., 2020). Products containing BCP may be applied pre‐emergence or post‐emergence (e.g., Benoit, 2019); however, superior control has been observed with post‐emergence application (Burriss et al., 2018).…”