On-Farm Glyphosate-Resistant Palmer Amaranth Management In Roundup Ready Flex, Liberty-Link, and Conventional Cotton Varieties

Deltapine 1048 B2RF, FM 1845 LLB2, and CT 210 cotton varieties were planted on farm in Barbour county, Alabama in an area infested with glyphosate-resistant palmer amaranth. Optimum weed management systems for each variety was used to control palmer amaranth from burndown through layby.  A combination of soil-residual and foliar herbicides with different modes of action was used for each variety.  Visual weed control ratings, palmer amaranth weed counts after final herbicide applications, and seed cotton yields were obtained for each variety and weed management system.  Economic calculations for gross and net returns were obtained based on weed control input costs (including herbicides and hand weeding), and seed cotton yield and quality.