Expert Urges Early Season Weed Control
Published: Friday, April 10, 2026
The MSU field crops virtual breakfast featured Christy Sprague, MSU Extension weeds specialist and professor, at their weekly meeting last Thursday, who gave recommendations concerning early season weed control.
Sprague discussed options, weed control in winter wheat and cover crop termination. She said that the key to a clean field is soil-based, or pre-emergence, herbicides.
"If I stress anything today, one of the things is that those pre-emergence herbicides are really important," Sprague said. "What they do is really provide a foundation for some of our harder-to-control weeds as well as herbicide resistant weeds."
Pre-herbicides also provide more consistent control, reduces weed presence after herbicide application and provides flexibility for post application. Sprague reminded farmers that soil-applied herbicides should be applied after tillage or in the burndown treatment.
She showed a photo of two soybean fields with herbicide applications, one with a pre-emergence application and regular treatments, and the other with just the regular treatment. The field with pre-emergence herbicide had clean rows, while the field with just regular treatment had some weed growth between rows.
"One of the things that we really want to do as we look towards the field season starting out is whatever crop your planting, probably one of the most important things is to make sure you're starting clean," she said.
There are two ways to prepare the field to accomplish this: tillage and burndown.
"We're looking at trying to till small weeds, particularly when field conditions are conducive, so we don't want them too wet; we can cause some problems, particularly with compaction," she said.
Sprague encouraged farmers to consider any weeds that would be too large or are susceptible to matting, such as chickweed, noting that a burndown could assist with those harder-to-control weeds.
Another consideration with spring tillage is tillage tools. Sprague said some vertical tillage tools have been found ineffective for weed removal, especially with larger weeds.
"It's really important to think about what tillage tools, if you're doing tillage, that you have," she said.
She added that aggressive tillage can eliminate weeds that germinate from the surface, such as horseweed, by burying them deeper beneath the soil.
Burndown is the process of eliminating weeds or cover crops by herbicide application.
Sprague listed three one-effective sites of action, including 2,4-D with glyphosate, Sharpen with glyphosate and MSO, and Liberty Ultra. For two-effective SOAs, she named 2,4-D ester with Sharpen, glyphosate and MSO; Sharpen with Liberty and MSO; Liberty Ultra and Metribuzin; and Gramoxone SL with Metribuzin.
The one-effective SOAs are specific to controlling glyphosate-resistant horseweed and marestail.
"One of the things you always need to think about is if we are applying 2,4-D prior to planting soybeans, unless they are the Enlist E-3 soybeans, we'd need to have at least seven days prior to planting," Sprague said.
Recently, the Environmental Protection Agency re-registered Dicamba, including formulations Stryax, Engenia and Tavium.
"In addition to either having good tillage or burndown, it's really important to make sure that we have some good residual products out there," Sprague said.
Moving to the topic of winter wheat, Sprague implored farmers to apply herbicides only when weeds are actively growing.
"One of the things we don't want to do is make those applications when the crop is under stress," she said.
A lot of that stress is related to temperatures. Sprague said a good standard is to apply herbicides to winter wheat only when the daily temperature is 50 degrees F or higher. She also recommends watching wheat growth size.
Sprague also discussed cover crop termination options.
A study with early termination, on April 1, compared to a late termination, on April 15, showed a difference between temperature affect on the cover crops. Sprague said the early termination occurred before the cover crops could "soak up" the herbicide applications, while the late termination allowed time for the spring temperatures to stimulate growth in the crops.
"We had some nice days between 50-70 degrees, and really those cover crops began to actively grow again, and that's where we saw much better control," she said, referring to the late termination strips.
Sprague's take-home message for farmers was to prepare with a comprehensive weed management plant with considerations for potential herbicide-resistant pests, start the year out clean, utilize soil-applied herbicides to reduce pressure on post herbicides, and consider temperature, growth stage and other factors when applying herbicides to wheat.
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