Cover Crop and Postemergence Herbicide Integration for Palmer amaranth Control in Cotton

• Published in: Weed technology Vol. 31; no. 3; pp. 348 - 355
• Main Authors: Wiggins, Matthew S, Hayes, Robert M, Nichols, Robert L, Steckel, Lawrence E
• Format: Journal Article
• Language: English
• Published: New York, USA Cambridge University Press 01.06.2017; Weed Science Society of America
• Subjects: Conservation agriculture; cultural weed control; resistance management; WEED MANAGEMENT-MAJOR CROPS
• ISSN: 0890-037X; 1550-2740
• DOI: 10.1017/wet.2017.10

Field experiments were conducted to evaluate the integration of cover crops and POST herbicides to control glyphosate-resistant Palmer amaranth in cotton. The winter-annual grasses accumulated the greatest amount of biomass and provided the most Palmer amaranth control. The estimates for the logistic regression would indicate that 1540 kg ha-1 would delay Palmer amaranth emerging and growing to 10 cm by an estimated 16.5 days. The Palmer amaranth that emerged in the cereal rye and wheat cover crop treatments took a longer time to reach 10 cm compared to the hairy vetch and crimson clover treatments. POST herbicides were needed for adequate control of Palmer amaranth. The glufosinate-based weed control system provided greater control (75% vs 31%) of Palmer amaranth than did the glyphosate system. These results indicate that a POST only herbicide weed management system did not provide sufficient control of Palmer amaranth, even when used in conjunction with cover crops that produced a moderate level of biomass. Therefore, future recommendations for GR Palmer amaranth control will include integrating cover crops with PRE herbicides, overlaying residual herbicides in-season, timely POST herbicide applications, and hand weeding in order to achieve season-long control of this pest. Nomenclature: Glufosinate, glyphosate, Palmer amaranth, Amaranthus palmeri S. Wats., cereal rye, Secale cereale L., cotton, Gossypium hirsutum L., crimson clover, Trifolium incarnatum L., hairy vetch, Vicia villosa Roth., winter wheat, Triticum aestivum L.