What is in this article?:
- Panel discussion at Pigposium discusses on-farm methods, costs, suggestions for control of glyphosate-resistant pigweeds.
- How deep into the fall should a farmer chop pigweeds?
- How to keep ditch banks clean?
Following a full day of speakers expounding on specific pigweed-related topics, the recent PigPosium wrapped up with a more free-wheeling panel discussion. Among those on stage to answer audience questions: Arkansas farmers David Wildy and Adam Chappell along with Bob Scott and Jason Norsworthy, weed scientists with the University of Arkansas Division of Agriculture.
Addressing how researchers approach programs that work for farmers, Scott said “it’s important to remember how we come up with recommendations. Adam (Chappell, Woodruff County farmer who spoke on measures taken to alleviate pigweed pressure on his farm) mentioned starting (a spray program) on cotyledon cotton, and risking some injury, in order to have the time to get across so many acres.”
When writing recommendations, “there are a lot of products we look at,” continued Scott. “And farmers point out more to me: Prefix early post and others. And some of those work and look pretty good.
“But one thing I try to keep in mind is putting (a product) in the mix that will buy growers time to get across 500 or 1,000 acres; or, get across a few acres while you’re planting some other crop at the same time.
“Just like the example of using residuals in LibertyLink soybeans. I think it buys you up to 21 days … as long as (the product) has some pigweed activity. It really frees up the post timing.
“I hear guys say, ‘I just want to make two shots of Ignite.’ We’ve talked today about why that’s a potential resistance issue. But I think, just from a practical management standpoint, it frees up a lot of time if you can get that first shot activated and have time to come back with a post. The same is true with using Prefix or something like that in Roundup Ready beans.”
How much did you spend per acre chopping in 2010?
“We were probably in the $20 per acre range,” said Wildy, who farms with his sons in Manila, Ark. “In years past, we were at $3 to $5.”
“I’d say $15 to $20 per acre,” said Chappell, who farms in Woodruff County. “We had two guys walking our farm. It would take a couple of weeks to get over it and they did it two or three times.”
How deep into the fall does a grower need to chop pigweeds?
“Basically pigweed flowers in response to day length,” said Norsworthy. “At the first of October, I’ve seen a pigweed emerge. Generally, you need two to three weeks of growth on that pigweed before it starts to produce seed…
“If you go four or five weeks without walking a field there can actually be resistant seed — or seed from a pigweed that’s emerged late — being produced.”