Resist herbicide resistance with prudent treatments, cover crops, rotations
The news of growing herbicide resistance in big species like waterhemp and Palmer amaranth is spawning a lot of talk about the different ways you can prevent resistance, both naturally or through herbicide. So, what's your preferred way to avoid herbicide resistance in your fields?
Ed Winkle's seen first-hand the problem resistant weeds can pose. The Martinsville, Ohio, farmer, certified crop adviser and Agriculture.com Crop Tech Tour correspondent just returned from a trip around the mid-South, where resistant Palmer amaranth bas become a "huge problem." Upon returning to his area, Winkle examined his own plans for weed control without resistance.
"We have to be careful not to ruin herbicide trying to save Roundup Ready crops. It all makes me happy I have stayed with non-GMO corn and switched back to non-GMO soybeans for a more total weed control solution," Winkle says. "We have weeds and we have too many resistant weeds!"
Winkle also has cover crops on his rotation roster, something other farmers say don't fit as well with their cropping systems. "While we all like the cover crops for tons of reasons, we never get enough fall growth for them to keep the winter annuals out of the field," says Arcadia, Indiana, farmer Ken Rulon. "So, a spring 2,4-D application is required. Actually, our worst marestail problems have come in fields where we had the best cover planted in early September. I think the planter helped seed them in."
It's the time crunch for getting cover crops sown among all other fieldwork, as well as a lack of results thus far, that is keeping Macon, Illinois, farmer Paul Butler from implementing cover crops on a large scale on his farm yet.
"2,4-D is stocked in the shed ready for fall spray -- just like it was last year when we finished harvest on December 5. I hope to put it on every acre this year," Butler says. "I am not seeing the benefits [of cover crops] here yet. Still experimenting. Tried radishes, but have got to seed earlier. Tried rye -- looked good but didn't show any difference on the yield monitor. Long story short, I've got to see results on small scale before I can invest money on larger scale (meaning buy a drill)."
Though this year's shaping up differently than last year's drawn-out, late harvest, Butler adds it's tough enough to get harvest and fall fertilizer applications completed before winter sets in, and at this point, fall spraying and cover crops rank 3rd and 4th on his fall priority list, respectively.
Whatever you plan to do to attack weeds and possible herbicide resistance in your fields, Winkle says it's important to have a plan in place, one that can be carried out under time constraints like Butler's facing. And, don't rule out other field operations in how they might contribute to resistance.
"Every farmer needs to think out a plan like you have. I know we all need to use more residual chemical and quit putting so much pressure on a few good chemicals. 2,4-D is an important tool in that toolbox," he says. "I noticed volunteer beans in the wheat and even more marestail disturbed by the drill, right in drill paths. A good job of combining and excellent residue spreading is a must for more reasons than reducing resistant weeds."