Glyphosate-resistant (GR) volunteer corn is a significant problem weed in soybean grown in rotation with corn in the midwestern United States and eastern Canada. The objective of this study was to evaluate the efficacy of glufosinate applied in single or sequential applications compared with acetyl-coenzyme A carboxylase (ACCase) inhibitors applied alone or tank mixed with glufosinate for controlling GR volunteer corn in glufosinate-resistant soybean. At 15 d after early-POST (DAEP), ACCase inhibitors applied alone controlled volunteer corn 76 to 93% compared to 71 to 82% control when tank mixed with glufosinate. The expected volunteer corn control achieved by tank mixing ACCase inhibitors and glufosinate was greater than the glufosinate alone, indicating that glufosinate antagonized ACCase inhibitors at 15 DAEP, but not at later rating dates. ACCase inhibitors applied alone or tank mixed with glufosinate followed by late-POST glufosinate application controlled volunteer corn and green foxtail ≥ 97% at 30 DAEP. Single early-POST application of glufosinate controlled common waterhemp and volunteer corn 53 to 78%, and green foxtail 72 to 93% at 15 DAEP. Single as well as sequential glufosinate applications controlled green foxtail and volunteer corn greater than or equal to 90%, and common waterhemp greater than 85% at 75 d after late-POST (DALP). Contrast analysis suggested that glufosinate applied sequentially provided greater control of volunteer corn at 15 and 75 DALP compared to a single application. Similar results were reflected in volunteer corn density and biomass at 75 DALP. Volunteer corn interference did not affect soybean yield, partly because of extreme weather conditions (hail and high winds) in both years of this study.
Nomenclature: Clethodim; fenoxaprop-P; fluazifop-P; glufosinate; quizalofop-P; sethoxydim; common waterhemp, Amaranthus rudis Sauer; green foxtail, Setaria viridis (L.) Beauv.; soybean, Glycine max (L.) Merr.; volunteer corn, Zea mays L.
El maíz voluntario resistente a glyphosate (GR) es un problema significativo de malezas en soja producida en rotación con maíz en el centro oeste de los Estados Unidos y en el este de Canadá. El objetivo de este estudio fue evaluar la eficacia de glufosinate aplicado solo o en aplicaciones secuenciales comparado con inhibidores de acetyl-coenzyme A carboxylase (ACCase) aplicados solos o en mezclas en tanque con glufosinate para el control de maíz GR voluntario en soja resistente a glufosinate. A 15 d después de la aplicación POST temprana (DAEP), los inhibidores de ACCase aplicados solos controlaron el maíz voluntario 76 a 93% comparado con 71 a 82% de control con la mezcla en tanque con glufosinate. El control esperado de maíz voluntario con las mezclas en tanque con ACCase y glufosinate fue mayor que el de glufosinate solo, lo que indicó que glufosinate antagonizó a los inhibidores de ACCase a 15 DAEP, pero no en fechas de evaluación posteriores. Los inhibidores de ACCase aplicados solos o en mezclas en tanque con glufosinate seguidos de aplicaciones tardías POST de glufosinate controlaron el maíz voluntario y Setaria viridis ≥ 97% a 30 DAEP. Aplicaciones POST tempranas de glufosinate solo controlaron Amaranthus rudis y maíz voluntario 53 a 78%, y S. viridis 72 a 93% a 15 DAEP. Aplicaciones solas y secuenciales de glufosinate controlaron S. viridis y maíz voluntario en 90% o más, y A. rudis más de 85% a 75 d después de la aplicación POST tardía (DALP). Análisis de contrastes sugirieron que glufosinate aplicado secuencialmente brindó mayor control del maíz voluntario a 15 y 75 DALP al compar
