To improve control of glyphosate-resistant pigweed, Adam, DeWayne and Seth Chappell went to residual herbicides and hooded sprayers. But there was one other management practice critical to getting the residuals out in a timely manner. The Chappells had to — if you’ll excuse the expression — hump it.
Adam Chappell, who will participate in a panel discussion on resistant pigweeds at the PigPosium on Nov. 17, at East Arkansas Community College, in Forrest City, Ark., farms cotton, soybeans, and milo with the help of seven hands and his brother and father, near Cotton Plant, Ark., in Woodruff County.
The Chappells first heard rumblings of glyphosate-resistant pigweed appearing in Mid-South fields about five years ago, and decided to add Dual into their weed control program as a precautionary measure. The farm had been relying on a total post program using glyphosate on Roundup Ready crops.
“That year, I noticed one spot (of pigweed) about the size of a pickup truck in one cotton field,” Adam said. “We coated it down with glyphosate, chopped it and took the weeds to the edge of the field.
“We did everything we were supposed to do, but the next year, we were seeing more spots, and they seemed to be getting progressively worse. So the next year, we went with Dual again and laid by with Valor. Then the next year, we put either Direx or Cotoran down behind the planter. We’ve been adding more and more residuals every year. This year, we added MSMA and Caparol between the Dual and the layby.”
So far, overlapping residuals have done a good job, and pigweeds have not gotten out of hand, according to Adam, although the farm will occasionally resort to hand chopping where patches of resistant pigweed pop up. “Last year was probably our worst year, because it rained so often we couldn’t get our timings right. The weeds would get too big, or emerge before we could get our residuals out.
“We had to rely on the hoe quite a bit, but it never got out of control, not like some of the horror stories I’ve heard about. If you hang on to glyphosate only, you’re going to get overrun.”
Chappell says resistant pigweed has been a problem across all the Chappells’ crops, although “it’s harder to control in cotton. We have a few more over-the-top options for soybeans.”
The Chappels were on schedule to finish cotton harvest this season by Oct. 15, which should give them plenty of time for fieldwork this fall. But fall work will consist mostly of seeding a cover crop for soil enhancement. “It’s been so dry, there are not a lot of pigweeds germinating right now.”
Chappell says he relies on Arkansas Extension weed specialist Ken Smith for advice on glyphosate-resistant pigweed, but he adds his own twist. “I have a lot of respect for Ken’s zero tolerance concept (doing whatever is necessary to prevent pigweed from going to seed), but my budget dictates how much tolerance I can have for pigweed. Right now, I’d be hard pressed to have somebody chopping or spraying the last few in the field. We’re right in the middle of harvest. It’s not possible for us. Our philosophy is to try and knock them down early.”
That doesn’t mean Chappell isn’t alarmed about a pigweed or two poking up in a field. “They say there are 250,000 seeds on one plant. I’ve seen some pretty big pigweeds out here.”
To get out residuals across 3,000 acres of cotton, the Chappells use three hooded sprayers, “but we really need five.”
Adam says the biggest change the farm has made for control of resistant pigweed “is prioritizing weed control. Like this year, we were in the middle of planting soybeans, and we had to put them on the back burner for a few days to get caught up on cotton spraying.”
They had to hustle to accomplish the task. “Timing is everything,” Adam said. “We don’t want pigweed to emerge. If you let them emerge, you’re too late. So we try to overlap our residuals. Direx is supposed to hold them for 10 days, so we start putting our Dual out at six days. It’s all about the timing and being relentless with them. You can’t ever let them get their heads above water. We run our hoods before we irrigate and we’ll even run them a couple of more times after we irrigate.”
Chappell acknowledges that one criticism of an overlapping residual program “is that there aren’t enough hours in the day to accomplish it. I disagree with that. We farm quite a few acres, and we get residuals on everything we farm, even on soybeans.”
Chappell has also worked hard to prove to himself and others that the residual program works by leaving out strips without them in cotton and soybeans.
There was a big difference — clean fields where residuals were used, pigweeds infesting the check plots.
Despite his success so far, Chappell doesn’t think he has the persistent weed wrapped up. “We’re always a missed timing or a missed rain from going from manageable to a nightmare. Sometimes it’s hard to get a good plan together without something going wrong.”
Chappell will discuss his weed control program in further detail at the PigPosium, Nov. 17 at East Arkansas Community College in the Fine Arts Center Auditorium in Forrest City, Ark. The event, sponsored by Delta Farm Pressand University of Arkansas Cooperative Extension Service, will begin at 8:45 a.m. and conclude at 3 p.m.
For more on the PigPosium, see http://deltafarmpress.com/soybeans/get-early-start-pigweed-pigposium.