Managing glyphosate-resistant Palmer pigweed

Published on: 16:04PM Jul 24, 2009
The spread of glyphosate-resistant Palmer pigweed is a real threat, due to several factors:
  • Limited control options
  • High seed production easily replenishes seedbank
  • Fiercely competitive for high yield loss potential
    • Cotton – 1 plant/20 feet of row can reduce yield 7%*
    • Soybeans – 0.1 plants/sq. ft. can reduce yield 33%*
    • Corn – 0.2 plants/foot of row can reduce yield 11%, while 2.4 plants/foot of row can reduce yield up to 91%**
  • Potential for pollen-mediated movement of resistance genes 
Last year, researchers in Tennessee found Palmer populations that withstood 152 oz/A of glyphosate and still survived.  
Because of Palmer pigweed, weed control costs have increased $30 to $50 an acre in many areas. Plus, the failure of herbicide options means some growers have to turn to tillage, threatening conservation tillage systems.
The Solution Builder on can help growers find solutions for this tough weed. This is a very good site to get you thinking about your weed control options, and it’s free. Several of our recommendations for Palmer include pre-emerge residual herbicides. You just don’t want this weed emerging.
Has Palmer pigweed become a larger problem in your area? How have you addressed it? Have you seen your weed control costs increase?