MANAGEMENT OF PALMER AMARANTH USING TILLAGE, RYE AND HERBICIDES IN SCREVEN COUNTY
Agronomy & Pest Management
Ray Hicks
County Extension Coordinator
University of Georgia
Sylvania
Abstract
Glyphosate-resistant Palmer amaranth is a major problem for producers in Georgia. Current research efforts for controlling glyphosate-resistant Palmer amaranth include a combination of cultural (rye cover crop), mechanical (deep plowing or tillage) and chemical (residual herbicide) strategies. Preliminary results from small-plot trials have been promising; in combination, these methods substantially improve our ability to manage Palmer amaranth. In 2011, research trials were established to scale up the small-plot studies to the “field” level in order to evaluate the efficacy of this combined program in a real world setting. One such study was conducted in Screven County, GA. The 3 treatments included: cotton strip – tilled into weeds without deep tillage (bare ground); cotton strip – tilled into fall-planted, spring-killed and rolled rye without deep tillage (rye-deep tillage); and cotton strip-tilled into fall-planted, spring-killed and rolled rye with deep tillage (rye+deep tillage). Each treatment was applied to an area that was approximately 3 acres in size. Weeds in each system were managed using the same Roundup (glyphosate) based herbicide program, which included the used of residual herbicides at-planting. With respect to Palmer amaranth density, infestations were larger in the bare ground and the rye-deep tillage treatments as compared to the rye+deep tillage treatment at all observation periods (PRE, PT1, PT2). Although this is not recommended for all acres, the use of deep tillage in combination with rye cover crop and an herbicide program that utilizes residual herbicides may help with the management of Palmer amaranth populations in heavily infested fields.
Authors: Hicks*, R.
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Hicks*, R. County Extension Coordinator, Georgia Extension, Georgia, 30467