A couple of months ago I wrote about glyphosate resistant weeds. Since then, I’ve had the opportunity to travel to Memphis for a conference sponsored by Bayer. After spending a day touring soybean fields full of resistant weeds, and hearing from farmers whose farms are being overrun by giant pigweeds, I've decided that my original article was woefully inadequate in telling the whole story.
Agriculture faces many problems, but glyphosate resistance may be the biggest one of all.
Mid South: first and worst The Mid South region has seen the problem first and worst, because of cultural challenges faced by farmers there - the most important being the lack of crop rotation.
Farmers in the Delta may not be able to rotate because the landowner owns a cotton gin and requires that cotton be grown; or, the owner has leveled the land for rice and wants a return on his investment; or, if the land isn’t irrigated, rotation isn’t an option because continuous soybeans are a must.
The corn-soybean rotation most of us use here in the Midwest allows us to alternate herbicides and modes of actions. Not only that, but long growing seasons in the South mean that weeds can reproduce after harvest.
Cotton takes several applications of various pesticides, and Roundup is used numerous times during the growing season, often at reduced rates. Farmers worry about drift and the application of glyphosate to non-GMO crops, so everyone uses glyphosate, and often no other herbicides are applied.
To be honest, you couldn’t devise a system more likely to produce resistance, and that’s exactly what happened.
"Growed up mess" Some fields are so full of pigweed that other weed species have been choked out. The weeds are so thick that they undergo drought stress within 7 days of emergence, leading to reduced effectiveness of any herbicide. Southern farmers call this a “growed up mess,” and that’s a pretty good description of what I saw.
Before my tour of the Delta, I was intellectually convinced that we had a problem, but emotionally, I guess I hadn’t accepted what was headed toward the Midwest.
My friend Charlie Kruse, who farms in the Boot heel of Missouri where the problem is huge, reports that his neighbor has had 70 people chopping pigweeds with hoes for a month.
As the saying goes, I don’t want to be that guy.
We in the Midwest are lucky, because we still have a chance to avoid the worst of the problem. Liberty Link and even some old standby herbicides provide us a chance to rotate modes of action. I’m sure that it would be a good cultural practice to start using Treflan again, where our tillage and conservation plans allow.
In the Delta, crop rents are decreasing because of weed pressures. Surely Midwestern landowners and farmers will take preventive action to protect the value of their investment. Or will we?
One thing is for sure – it's going to take more intensive management to handle the problem. That has some implications for the size of farms. It may not be possible to cover as many acres if more tillage is needed, or if different chemical regimes are necessary for different fields. Are the good times brought to us by Roundup over forever?
One weed scientist at the conference, who is the world’s leading expert on glyphosate resistance, said that glyphosate has been as important to the production of food as the discovery of penicillin was to medicine. That’s an amazing statement that brings home the central truth that must be learned by farmers: nothing is more important to the future of our industry than protecting this technology.
On my farm, I’m planning on taking a year off from Roundup, controlling weeds with Liberty Link in soybeans and some old standby methods in corn.
As the moderator of the conference pointed out, we owe it to our children and grandchildren to protect the value of this technology. Perhaps, as is usually the case, my wife said it best: Our generation of farmers does not want to be responsible for Paradise Lost.