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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #120198

Title: GLYPHOSATE/MSMA MIXTURES IN GLYPHOSATE-RESISTANT COTTON (GOSSYPIUM HIRSUTUM)

Author
item CULPEPPER, A - UNIVERSITY OF GEORGIA
item YORK, A - UNIVERSITY OF GEORGIA
item Webster, Theodore

Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2001
Publication Date: 10/1/2001
Citation: Culpepper, A.S., York, A.C., Webster, T.M. 2001. Glyphosate/MSMA mixtures in glyphosate-resistant cotton (Gossypium hirsutum)[abstract]. Weed Science Society of America Abstracts. 41:6.

Interpretive Summary:

Technical Abstract: Nutsedges are some of the most troublesome cotton weeds. Glyphosate controls most weeds in transgenic cotton, but nutsedge is only suppressed. MSMA has routinely been used for nutsedge control, but MSMA only suppresses nutsedges at rates registered for over-the-top application. Combinations of glyphosate and MSMA may improve control. Field and greenhouse studies were conducted in Georgia and North Carolina to compare nutsedge control and cotton injury by glyphosate and MSMA applied alone and as a tank mixture. Treatments included five glyphosate rates and four MSMA rates arranged factorially. In the greenhouse, glyphosate at 0.5 to 1.0 lb/A controlled purple nutsedge 8 to 15% greater than yellow nutsedge. In contrast, MSMA was at least 12% more effective on yellow nutsedge. MSMA at 0.5 lb/A mixed with glyphosate did not increase nutsedge control. Adding 1.0 lb/A MSMA to glyphosate increased yellow nutsedge control at least 10%; purple nutsedge was less responsive. The addition of MSMA was beneficial only with low rates of glyphosate. MSMA at 2.0 lb/A controlled yellow nutsedge 81 to 93%; tank mixes with glyphosate at this rate were not synergistic. MSMA at 1.0 lb/A improved yellow nutsedge control in the field 17 to 28% with low rates of glyphosate. Glyphosate at 1.0 lb/A controlled yellow nutsedge 71%. MSMA at 2.0 lb/A controlled yellow nutsedge 81 to 89%. Glyphosate alone did not injure cotton. MSMA at 0.5, 1.0, and 2.0 lb/A injured cotton 4, 10, and 21%, respectively. Injury with mixtures increased as glyphosate rate increased.