- Increasing populations of glyphosate-resistant pigweeds lead to loose group effort to deal with problem.
- Cotton producers' fields, turnrows and ditches noticeably cleaner of resistant weeds following 'zero tolerance' growing season.
- Control programs discussed.
COTTON PRODUCER MIKE Morgan, member of a group of ‘zero tolerance’ farmers in Arkansas’ Clay County, quickly dispatches any Palmer amaranth he finds. “Whenever anyone on the farm is riding down the turnrow, watering, whatever, and sees (a pigweed), we go get it.”
It’s late September and Mike Morgan reckons his cotton will be ready to pick in three or four days. That means there’s plenty of time to deal with a flush of glyphosate-resistant Palmer amaranth he’s discovered in a ditch bottom not far from his shop.
“We’ve really become serious and intent about dealing with this,” says Morgan, who farms large cotton acreage outside Piggott, Ark. “When we see a flush coming on, it’s sprayed. Period. This season, some of the turnrows and ditches in these fields have been sprayed three times. Almost all of them were sprayed twice.
“We use a residual mixed with Gramoxone and it holds up for a while. But it will wear out and here comes another flush of pigweeds. It’s amazing how fast they’ll grow – barely up one day then, turn around, they’re 18 inches tall.”
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In 2009, the pigweeds “really started worrying us. It gradually got worse and then, last year, they took off. Honestly, if we hadn’t dealt with this like we have, I can’t imagine how bad it would have gotten. I think pigweed would have taken over whole fields.”
Morgan’s enthusiasm for killing pigweeds isn’t isolated in extreme northeast Arkansas’ cotton-friendly Clay County. Alarmed at the tide of resistant pigweeds that threatened to wash over their land, area producers have loosely banded together – adopting the “zero tolerance” of pigweeds favored by state weed scientists -- to protect their land and future. Mass adoption of the approach is obvious while driving Piggott-area turnrows and back roads that are clean of weeds. The contrast with pigweed-heavy sections of the Delta is striking.
Greg Engle, who farms not far from Morgan, began to see a lot of resistant pigweeds about two years ago with “the problem getting worse in turnrows. It seems like it hit us a little later than some folks in the state.”
Even before Roundup Ready cotton, Engle was using broadcast hooded sprayers to treat ditches and turnrows.
“We’ve always tried to keep things clean – and Roundup was pretty cheap and that’s what we used. So, we’d been doing it so long, that’s where the pigweeds began showing up.”
When the pigweed problem started, Engle had “choppers work ditches and turnrows. At that time, the pigweeds weren’t really thick so it didn’t cost too much.”
Last year, “we brought the choppers in again when the pigweeds were a little worse. After a little while, we realized we needed to add something to our plan. But, even then, there weren’t too many pigweeds in the fields. They were mostly in the ditches and on the borders.”
That led Engle to use the broadcast hooded sprayer. “That way we didn’t have to worry about drift on the cotton. The sprayer has several sections that can be adjusted. That way you can spray either a small spot or a larger one.
“We use Gramoxone (at 2.5 percent or, if the generic version, 2 percent) and Ignite (2.5 percent). We also use several residuals – Valor, Dual or Direx. If you can stay timely and get the pigweeds when they’re pretty small, that mix will smoke them.”