What is in this article?:
- Palmer amaranth hits Georgia cotton
- Resistance changes management
- Early, aggressive action
He said deep tillage may be a key. Palmer amaranth emerges from a shallow depth, he said, and seed life is not as long as once thought. “Seed require a lot of light to emerge so deep tillage, putting the weed seed 4 inches deep, will help.
“Make smart decisions over the next few years.”
Culpepper said “not one acre of Georgia cotton will be planted without an incorporated herbicide in 2010.
“We’re also using hooded sprayers. We can tank-mix Roundup and Diuron or Caparol. Every acre in the state will get a directed spray or hooded sprayer application,” he said.
Culpepper did a little math exercise to show how fast the problem can develop into a nightmare.
The first year, consider that five Palmer amaranth female plants escape and produce 2 million seed, of which 50 percent germinate. The following year an aggressive weed control program takes out 99 percent of the Palmer amaranth population, leaving 1,000 plants at harvest and 400 of them female. That means 160 million seed, which, at 50 percent germination, leaves 80 million.
Assuming another aggressive weed control program and another 99 percent success rate, 80,000 plants survive the next year, with 50 percent germination.
The next generation would be 1.28 multiplied by 10 to the tenth power, which equals – disaster.