Timing of Fall Residual Herbicides for Control of Glyphosate-Resistant Italian Ryegrass

Glyphosate-resistant Italian ryegrass continues to spread across the Mississippi Delta, and it poses a serious threat to crop production systems in the Midsouth if left uncontrolled.  The presence of this weed also jeopardizes a typical glyphosate-based burndown program.  Fall management options can provide excellent control of this weed and hopefully help to prevent the spread of this GR weed.  Research conducted from 2006 through 2009 identified fall applications of residual herbicides as the most effective means of managing glyphosate-resistant Italian ryegrass.  Fall applications of Dual Magnum, Command, and KIH-485 provided residual control that held until spring.  Research was conducted in Stoneville, MS, to evaluate application timings of residual herbicides applied in the fall.