Culpepper said just two plants per 20 foot of row can reduce yield by 23 percent. “It’s also a harvest efficiency disaster.”

He said cotton farmers have to learn how to control seed production from Palmer amaranth “or get out of cotton. A female plant produces a lot of seed, 300,000 to 500,000 per year. With that production, you only need one or two years before the weed becomes impossible to control economically. I prefer to get it in year one.”

He said plants also spread with pollen movement.

Culpepper said that even with excellent control as high as 99 percent, resistant Palmer amaranth seed production “will overwhelm us. We can’t do better than 99 percent.”

Ignite can be effective but has to be applied on a timely basis. If not, plants may be just stunted and will come back. “If you don’t get it the first time with Ignite, you probably will not,” he said.

So far, Texas has avoided the devastating resistance problems that have hammered Southeast and Mid-South cotton fields, but Culpepper recommends caution.

“Texas cotton farmers should accept the seriousness of the situation,” he said. “Georgia farmers took four years and now they are trying to catch up. Listen to your weed control specialists.”

He advises farmers to “pounce on small areas in a field” where suspected resistant weeds show up. “Pull them up. Don’t let them go to seed.

“Don’t expect new chemistry to save you. That’s not the answer. New ones will help but it will still take an aggressive program with Palmer amaranth. Rotate chemistry and develop integrated programs.”