• Glyphosate-resistant Palmer pigweed threatens to propel weed control through a time-warp.
• Solutions are emerging. One is zero tolerance.
• Zero tolerance attacks the Achilles’ heel of Palmer pigweed, its seed.
• Zero tolerance combines hand hoeing and supplemental herbicide application.
• Solutions won’t be cheap.
How many years?
Smith stopped short of saying how many years of zero tolerance it would take before a field could be returned to manageability again, “but the number of hours or days of hand weeding per acre is going to go down every year. If we ever let them get away from us and leave one out there, we can be in trouble again.”
It will require a change in perspective for cotton producers. “Thinking about how many pigweeds we can stand per row foot before we start losing yield is an antiquated mentality,” Smith said. “We need to start thinking about what we need to do today for next year.”
Pace Hindsley, who produces cotton around Marvell, Ark., is managing one of his cotton fields for zero tolerance, in cooperation with Smith. The field has been in continuous cotton for over 40 years, and has become infested in Palmer pigweed.
The first step in zero tolerance for Hindsley begins after burndown with a preplant application of Reflex. After planting cotton, Hindsley applied Sequence and Dual over the top of cotton. When cotton started squaring, he cultivated the cotton one time, followed by an application of Valor and Roundup under a hooded sprayer.
Weed control since then has been in the hands of hired choppers. “If we have any escapes, we manually chop them down ourselves,” Hindsley said.
Hindsley figures the hands have worked a total of about 1.5 hours per acre on the zero tolerance field, but he has invested as much as $50 to $60 per acre in hand labor on other problem fields. Palmer pigweed chopping crews are loaded for bear, carrying heavy duty hoes, a machete or two, and a sharp shovel.
“This is the magnitude of the problem,” said Smith, holding up a giant Palmer pigweed plant which resembled a small tree with a 3-inch diameter base.