What is in this article?:
- Resistant-weed solution not found in bottle
- Empty horizon
- Resistance to glyphosate is developing at the rate of at least one new weed per year.
- Weeds with documented resistance to glyphosate include horseweed, pigweed, giant ragweed, common ragweed, common water hemp, Italian ryegrass, goosegrass and johnsongrass.
- Yet, glyphosate-resistant Palmer pigweed is still the primary driver in weed control.
There are no new technologies on the horizon that can do what the Roundup Ready system used to do, Steckel said. “Nothing will be able to provide the efficacy on large Palmer like Roundup Ready did. In the next 10 years to 15 years, we’re going to have to manage it with the older herbicides, the preplant and pre-emergence herbicides and the new herbicide-technology traits.”
While the new traits, such as dicamba- or 2,4-D-resistance, won’t be a silver bullet for control of resistant weeds, “they will be very much needed,” Steckel said. “We will be able to do a better job of managing pigweed than we can today. We can kill that 5- to 8-inch pigweed very effectively with 2,4-D and dicamba. Hopefully, they will come in the nick of time. We’re relying a lot on Ignite and we’re relying a lot on these pre- herbicides, and I think we’re going to start to see resistance.”
Cover crops can also provide an answer, noted Steckel. “It’s actually a pretty good mode of action for Palmer pigweed, which needs three things to germinate, light, water and heat. If you can get some shade on the ground, you’re going to curtail germination.
Steckel says research could reveal new practices for control of resistant weeds. “There are a lot of things we need to take a look at, like row-width, or maybe getting back to some cultivation.”