Henry Gantz writes in Don’t Give Pigweed The Light Of Day, If it doesn’t come up, you don’t have to kill it that farmers were depending mostly on Roundup, but that no longer works, due to multiple mutant weeds, including pigweed and marestail. He quotes Dr. Larry Steckle, Extension weed specialist at the University of Tennessee:
Steckle said we’ve now reached the point where we have to begin thinking in terms of controlling “resistant weeds” instead of “resistant marestail” or “resistant Palmer pigweed” because they are both beginning to show up in the same field.So, what’s the solution:
“We have to manage them both,” he said. “There’s a new product from BASF called Sharpen that I’ve been looking at for five years and I’ve been very impressed with the marestail control. I still like dicamba, Roundup and Gramoxone.
“But if you have Palmer pigweed, too, then you’re going to have to overlap with residuals ― Cotoran, Caparol, Prowl ― to have any chance to do a good job of controlling them.”
Resistance to one herbicide or others across the Cotton Belt ranges from a high of 18 in California to none in Arizona. The Mid-South states average the highest.Ninety percent? So pesticides only do 10%? Why pay for them, then?
The most troublesome weed by far is Palmer amaranth, followed by marestail.
Georgia Extension weed scientist Dr. Stanley Culpepper said he’s fought it long enough to realize that the best control of resistant Palmer amaranth is to keep it from ever germinating.
“If you have dryland production in the Southeast, Mid-South and the Mid-Atlantic states and think you can go in with 50-something-dollar herbicides and control resistant Palmer amaranth without rain, you will lose,” he said. “If we integrate them with programs that deep-turn the land, we can reduce the amount of Palmer amaranth seed that emerges by 50%, and that greatly improves control. Conservation tillage growers can also do that by using a rye cover crop to reduce emergence.
“The goal is, if it doesn’t come up, you don’t have to kill it.”
Culpepper said when cover crops and deep tillage have been used together, resistant Palmer amaranth control has been improved by 90% in Roundup Ready programs.
This recommendation for plowing isn’t just a few researchers’ opinion. Here’s where they presented:
For the last three years, the Beltwide has kicked off with the Consultants Conference, sponsored by Syngenta, Bayer CropScience and Dow AgroSciences.One name is conspicuously missing there: Monsanto. Looks like the other pesticide companies are looking to horn in on Monsanto’s Roundup turf. But they only way they’ve found that works is to plow that turf.