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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #250027
Title: Palmer amaranth (Amaranthus palmeri) control as affected by herbicide, method of application, and winter cover crop

Author
item GREY, T.L. - University Of Georgia
item CULPEPPER, A.S. - University Of Georgia
item SOSNOKIE, L.M. - University Of Georgia
item Webster, Theodore

Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/26/2010
Publication Date: 2/1/2010
Citation: Grey, T., Culpepper, A., Sosnokie, L., Webster, T.M. 2010. Palmer amaranth (Amaranthus palmeri) control as affected by herbicide, method of application, and winter cover crop. Proceedings of the Weed Science Society of America. #PA-71.

Interpretive Summary:

Technical Abstract: Studies evaluated cover crop effect, herbicide application method, and residual PRE herbicides on control of glyphosate-resistant Palmer amaranth (PA) in cotton in Macon County GA during 2008 and 2009. Tillage methods were conventional, strip tillage in rolled wheat, or strip tillage in rolled rye. Herbicides were pendimethalin, S-metolachlor, fomesafen, and combinations of these, including a nontreated control (NT). Methods of application were spray or fertilizer impregnation. PA seedling emergence counts and early season visual control were taken through 60 days after treatment (DAT). The objectives were to determine herbicide residual control as affected by cover crops and if fertilizer impregnation improved crop safety to S-metolachlor and fomesafen. Cotton injury from herbicide application varied by year. In 2009 with intense rainfall, spray herbicide application had greater cotton injury than fertilizer impregnation. The S-metolachlor PRE treatments injured cotton 4-14% 18 DAT and 1-10% 35 DAT. Fomesafen and fomesafen+ pendimethalin PRE injured cotton <9%. All fomesafen treatments controlled PA >86% at 24 DAT and >72% at 43 DAT. Combinations of PRE pendimethalin, S-metolachor, or fomesafen controlled PA greater than when herbicides were applied alone. PA stand was reduced greatest by rye, then wheat, and conventional tillage. Spray application was more efficient for PA control than fertilizer impregnation.