How to cope with herbicide shortages
Talk with your chemical retailer. Study weed control guides compiled by your local land-grant universities. And above all, have a plan B or even plan C.
Those are ways farmers can deal with looming 2022 herbicide shortages, says Bill Johnson, Purdue University Extension weed specialist. It’s a difficult situation, since old standby chemicals are most impacted by shortages.
“The most consistent thing I heard is that glyphosate [Group 9] and glufosinate [Group 10] will be in short supply,” says Johnson. “More recently, I’ve heard that 2,4-D [Group 4] and some atrazine and mesotrione [Callisto, Group 27] formulations may be in short supply.”
Farmers without an alternative plan may find themselves in a difficult spot come April and May if they cannot access the chemicals they ordered, Johnson says. “It will be complete chaos to try to figure out how to deal with it at that stage."
Options exist if farmers cannot access glufosinate or glyphosate. For example, Group 2 (ALS) herbicides like Accent can substitute for grass control in corn, he notes.
“What you have to keep in mind is that corn growth stage is really important with these ALS herbicides,” Johnson says. “Once you get past V5 or V6, you’ll need to control grasses in corn with something else,” says Johnson. “They also work slower than glyphosate.”
ALS-resistant foxtail, shattercane, and Johnson grass also exist in parts of Indiana. “Most of these ALS inhibitors also don’t work well on crabgrass, either,” he says.
It’s particularly important in 2022 for farmers to know what type of weeds are present in their fields.
“When you know what weeds you are going after, you can be a lot smarter about picking herbicides,” says Johnson. “There are some apps you can put on your (cell) phone that can help out with weed identification.”
Weed Control Guides
Weed control guides published by land-grant universities, such as one written for Illinois, Indiana, and Ohio, can also aid farmers. These guides can help farmers:
- weigh advantages and disadvantages of different herbicide strategies ranging from preemergence to postemergence applications.
- assess herbicide rotational intervals.
- sort out which herbicides work best in certain situations.
- determine herbicide sensitivity in corn hybrids, such as sensitivity to ALS (Group 2, synthetic auxins (Group 4) or HPPD inhibitors (Group 27). Specialty corns, such as popcorn and white corn, are particularly sensitive to certain herbicides, says Johnson.
- know crop stage cutoff of herbicides.