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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #192033
Title: MANAGING GLYPHOSATE-RESISTANT PALMER AMARANTH (AMARANTHUS PALMERI) IN GEORGIA COTTON (GOSSYPIUM HIRSUTUM)

Author
item CULPEPPER, A - UNIVERSITY OF GEORGIA
item KICKLER, J - UNIVERSITY OF GEORGIA
item YORK, A - NC STATE UNIVERSITY
item GREY, T - UNIVERSITY OF GEORGIA
item Webster, Theodore

Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/12/2006
Publication Date: 2/13/2006
Citation: Culpepper, A.S., Kickler, J., York, A.C., Grey, T.L., Webster, T.M. 2006. Managing glyphosate-resistant Palmer amaranth (Amaranthus palmeri) in Georgia cotton (Gossypium hirsutum)[abstract]. Weed Science Society of America Abstracts. 46:59-60.

Interpretive Summary:

Technical Abstract: Studies were conducted in GA to evaluate control programs on a population of glyphosate-resistant Palmer amaranth. Glyphosate at 0.84 (1X use rate), 1.68, and 3.36 kg ae ha-1 controlled the weed >31%. Pendimethalin (0.94 kg ai ha-1) plus fluometuron (1.12 kg ai ha-1) PRE, glyphosate 0.84 kg POST, and glyphosate 0.84 kg plus diuron 0.84 kg ai ha-1 at layby provided 68% late-season control. Replacing fluometuron with pyrithiobac (0.048 ai kg ha-1) or fomesafen (0.28 kg ai ha-1) PRE improved control to 87 or 96%, respectively. Adding S-metolachlor (1.06 kg ai ha-1) with the POST glyphosate when following pendimethalin plus fluometuron, pyrithiobac, or fomesafen improved control (12%) only in the pyrithiobac system. When fomesafen plus pendimethalin were applied, excellent control was noted without S-metolachlor POST. Conditions were ideal with no drought or environmental stress throughout the season. Rainfall occurred within 72 hours of each herbicide application and even then only four programs provided acceptable control (>95% control). Two of these programs contained fomesafen PRE which is currently not labeled for use in cotton, one program contained two applications of pyrithiobac which will significantly promote continued ALS resistance development, and the final program contained pendimethalin plus pyrithiobac PRE, glyphosate plus S-metolachlor MPOT, and glyphosate plus diuron at layby.