Sponsored By
Farm Progress

A group effort to deal with resistant pigweedsA group effort to deal with resistant pigweeds

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.

David Bennett

October 19, 2011

7 Min Read
<p> COTTON PRODUCER MIKE Morgan, member of a group of &lsquo;zero tolerance&rsquo; farmers in Arkansas&rsquo; Clay County, quickly dispatches any Palmer amaranth he finds. &ldquo;Whenever anyone on the farm is riding down the turnrow, watering, whatever, and sees (a pigweed), we go get it.&rdquo;</p>

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.”

For related story, see here.

For photo gallery, see here.

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.”


Morgan has also employed chopping crews. “We’ve had one large and two smaller ones out. They worked over three months and chopped every day.”

His hoeing bill this season was “outrageous. But these pigweeds hide easily. We need the crews to go over the fields with (a keen eye). Pigweeds can hide out in the field middles. They’ll go to seed whether they’re six inches tall or 10-feet tall. And one little plant can send weeds over a big area.

“The first trip across the fields chopping was the hardest, and most expensive, to do. The second time was easier – although in the sandier fields the pigweeds were really bad in, we had to chop three times.”

Morgan’s operation still has pigweeds, but “very few. We’re doing our best. Whenever anyone on the farm is riding down the turnrow, watering, whatever, and see one, we go get it.”

There’s no choice, he says. “The number of pigweeds is exploding. I see them growing on gravel roads, in cracks of concrete. It’s unreal. I’ve seen them on the bridge going to Memphis – pigweeds just growing there out of the concrete. You shake your head and wonder ‘how in the world?’

Andy Vangilder, Clay County Extension staff chair, has “seen the same thing around construction areas. I’ve seen them growing around the concrete pilings along highways. How did they even get there?”

Engle agrees. “It’s a crazy weed. If you mow them, they’ll head out when they’re barely up. It’s almost like they have a mind of their own. They’re like kudzu – grow from nothing to huge in no time.”

Like Morgan, Engle has also been chopping and spraying all summer. “We’ve had five hands just chopping pigweeds most of the summer.

“Where the big winter rains back water up on our land it seems the pigweed seed are spreading. Everyone is sharing in this – seed moves in that water. That’s one reason why everyone needs to be vigilant and get these pigweeds. If you don’t, it will hurt your neighbor.”

Floods deposit pigweed seed in interesting ways, says Morgan.  A field rented for the first time this year is “around the St. Francis River. It completely flooded and after the water receded, it was odd how the pigweeds emerged. There were a few dotted out in the field interior but an unreal amount of pigweeds surrounded it.”

It can be done

Sparing a neighbor from pigweed seed must be a constant concern says Vangilder. “You just have to worry about the other fellow’s property. That has be an element in dealing with this problem. Everyone really is in this together.

“Mike and Greg were involved from the start. There may have been others, but they were among the first. They’ve certainly run with it and we now have a bunch of farmers involved. Even the two or three stragglers, after seeing how vigilant the rest have been, began taking care of their business later in the season.

“I’ve been with Mike and Greg, and listening on the radio, when they’re calling crews. Sometimes it’s almost constant: ‘I’ve seen some pigweeds in X and Y field. Come deal with them.’”

And maintenance is crucial.

“Something everyone needs to understand is you must keep after it until the cold really sets in,” says Engle. “You have to maintain. Two or three weeks ago, we kept thinking ‘well, this is the last week we’ll have to spray some pigweeds.’ But then there’d be another flush. We had to chop again” the week of September 19.

Early this year while surveying pigweeds emerging in his fields, Morgan admits he “actually felt some panic. I thought ‘This is something we can’t beat. We can’t win this battle.’ I didn’t think we could do it.

“But we decided to really make it hard on them and set in on chopping, running hoods and, sometimes, just pulled them ourselves. Finally, we began to see some progress.

“Hopefully, next year won’t be as bad as this one. And we’ll figure out how to control them cheaper. We’ve spent a lot of money on pigweeds this year. That was necessary because we’re determined to grow cotton and we’ll do whatever it takes.”

When looking at land to rent or buy, how big an issue is pigweed infestation?

“Well, nowadays, you have to consider the expense to make the land productive,” says Morgan. “If you’re looking to buy or rent a pigweed farm, you have to budget that in. It has to be cleaned up.

“So, it isn’t a factor that would kill a deal to buy or rent. But it’s something you have to keep in your mind – chopping, chemicals and all the rest.”

Asked about future plans to deal with pigweeds, Engle says he’ll stick with this year’s vigilant approach. “We’ll just get into it as early as possible. Weather dictates a lot of that and you just pray you won’t get behind. It can take a long time to get caught up if you’re planting late.

“We look at this as a ‘have to.’ There is no other option for us. You can see farms that have been left alone for too long and there are pigweeds wall-to-wall. It would be easy to make a farm nearly worthless and to a point where it could hardly be farmed. Pigweeds will absolutely take over.”

About the Author(s)

David Bennett

Associate Editor, Delta Farm Press

David Bennett, associate editor for Delta Farm Press, is an Arkansan. He worked with a daily newspaper before joining Farm Press in 1994. Bennett writes about legislative and crop related issues in the Mid-South states.

Subscribe to receive top agriculture news
Be informed daily with these free e-newsletters

You May Also Like