Improving Winter Wheat Yield and Quality by Controlling Italian Ryegrass (Lolium multiflorum LAM.) in Winter Canola

Abstract

Winter annual grasses are common weeds in Oklahoma's wheat production systems. To evaluate the extended control of Italian ryegrass, experiments were established in Oklahoma winter wheat fields in the fall of 2004. Cropping systems evaluated included continuous wheat, continuous canola, wheat followed by canola, and canola followed by wheat. In-season wheat herbicide treatments included imazamox applied to imidazolinone-tolerant wheat and mesosulfuron applied to conventional wheat, while in-season canola herbicides included quizalofop applied to conventional canola and glyphosate applied to glyphosate-tolerant canola. A cropping system including both wheat and canola with herbicide sprayed in each crop reduced Italian ryegrass density at harvest and increased yield when compared to continuous wheat. Control in a rotation with glyphosate-treated canola and mesosulfuron-treated wheat or two seasons of mesosulfuron-treated wheat controlled Italian ryegrass and yielded higher than consecutive seasons of glyphosate-treated canola or glyphosate-treated canola followed by nontreated wheat at most locations.