Arkansas farmers are expanding pigweed No Tolerance zones, while warm temperatures prompt precocious pigweeds to produce seedheads months early, said Ken Smith, extension weed scientist for the University of Arkansas System Division of Agriculture.
The Zero Tolerance concept of managing herbicide-resistant pigweed focuses on reducing the weed's seedbank in the soil by not allowing the weeds to create seeds.
Pigweed is prolific. Each plant produces between 250,000 to 1.5 million seeds. With that many seeds, pigweed can easily crowd out row crops and take profits from producers.
“I’ve been getting call after call from farmers saying the pigweed is already producing seed,” he said. Many of the pigweeds are tiny — just 3-4 inches tall.
The record-warm winter brought pigweed out of the ground early, and because pigweed reproduction is cued by day length, the young pigweeds were fooled into thinking it was fall, and began seed-making, Smith said.
The good news is that “I haven’t found a viable seed in one of them yet,” he said. “That’s not to say we won’t find one, but hopefully there’s not enough pollen to pollinate them.”
To deal with these early seeders, Smith said “we just spray them out before we plant.” Smith said the calls are a good sign that the Zero Tolerance idea is becoming more widely accepted and that growers are recognizing that controlling the seedbank is critical.
Last year, Zero Tolerance zones set up in Clay County proved successful as neighbors banded together to delete pigweed everywhere they found it, and before it produced seeds, in field margins, turnrows and even road rights-of-way.
This year, more cotton farmers in Clay County are joining the effort, said Andy Vangilder, Clay County extension staff chair for the University of Arkansas System Division of Agriculture.
“Most everyone is trying to get on board,” he said. “The guys who didn’t have a good year last year are trying to step up. The awareness is definitely there.”
And so is the early-seeding pigweed.
“I’ve had several people text and send me pictures of 3-4 inch pigweed with seed on it – in March,” Vangilder said. “That’s how resilient that weed is.”
Vangilder drew an analogy to boll weevil eradication. “People said we couldn’t get rid of the boll weevil, but we did,” he said. “While I don’t think we will eradicate pigweeds, if we have a positive attitude, then Zero Tolerance can work.”
Desha County will be the first one in south Arkansas to move to Zero Tolerance. “They’re taking an aggressive approach,” Smith said. “They called and said ‘we want this’.”
Desha County Extension Staff Chair Wes Kirkpatrick said more than a dozen producers, representing more than 20,000 acres of all types of crops in the county, attended a Zero Tolerance informational meeting.
And while herbicide-resistant pigweed is not as big a problem in the southeastern corner of the state as it is further north, “it’ll be here eventually because pigweed is prolific,” Kirkpatrick said.
“These growers are trying to cut it off at the pass and keep pigweed seed production at a minimum. They want to prevent a situation where you have to disk up 100 acres because you can’t do anything else. These guys are definitely trying to be proactive."
Smith said Crittenden County had also joined the Zero Tolerance effort.