Pigweed threatens 2009 Cotton yeild

Glyphosate-resistant Palmer amaranth (pigweed) is Georgia’s most problematic weed in cotton and is spreading rapidly. There are some cases documented in Seminole County. Two Palmer amaranth per 20 row feet of cotton can reduce yield at least 23%, and in dry land production in GA, a single female plant can produce 450,000 seeds when competing with DP 555 BRR cotton for the entire season.

Spread of this resistant pest is rapid through traditional means such as custom harvesting, lack of cleaning equipment, and spreading of infested materials, but the resistance trait is also moving rapidly via pollen. This pest threatens both conservation tillage and cotton production. Growers who have resistant Palmer amaranth must adopt aggressive management programs. More importantly, growers who do not have resistance must delay its arrival as there are no economical programs to manage this pest in cotton.