Managing Glyphosate-Resistant Italian Ryegrass Using Clethodim Based Programs

Glyphosate-resistant Italian ryegrass continues to spread across the Mississippi Delta, and its presence jeopardizes typical glyphosate-based burndown programs.  Clethodim is one of the few postemergence herbicides that consistently controls glyphosate-resistant Italian ryegrass.  Previous research with clethodim-based programs targeted application timings in the spring prior to anthesis of glyphosate-resistant Italian ryegrass.  However, applications at these timings required multiple applications for complete control.  Research was conducted in Stoneville, MS, to evaluate timings of postemergence herbicides applied in October, January, and March.