When it comes to starting clean and staying clean, the last few years have been challenging for preemergence herbicide programs. In Southern Illinois early season planting windows have been very tight due to excessive moisture. When soil temps warm up and hit the 50 degree threshold, most fields have remained too wet to plant. By the time it does dries out, soil temps are 60 degrees plus and we are right smack dab in the middle of peak waterhemp germination (Mid-May to Early June). This certainly puts a strain on our preemergence herbicide programs. So the question for 2026 is: How do we combat these challenges and better maximize our preemergence herbicide program?
There are three things we are going to focus on in regards to our preemergence programs. For starters, we are going to make sure we incorporate a residual herbicide with our spring burndown application. I believe it is imperative to add a residual herbicide, such a generic Valor (flumioxazin), with your glyphosate + 2,4-D spring burndown. Generic Valor is cost-effective and will give you 30-40 days of early season residual control. This keeps your fields clean and buys you time should we experience delayed planting once again.
Second, we are recommending preemergence herbicides with a minimum of three modes of action. Research studies from major universities continue to test new formulations of preemergence herbicides annually with the most effective containing 3 modes of action. One study I often refer to is Purdue University’s study from 2022. While a few new formulations have been launched since that study, the actives within those formulations are not new. The study is noteworthy in that it has tested each mode of action separately as well as in multi-mode of action formulations. Each active is ranked based on 28 DAT (Days After Treatment) for waterhemp control (See link below). This study aligns with what we are seeing in our neck of the woods. If you want the best control, you need three modes of action.
In addition to utilizing a three mode of action preemergence herbicide, we are going to incorporate Cohesion, a new adjuvant from Red Zone Technologies (A Wilbur Ellis Company). Cohesion was specifically designed to maximize the effectiveness of preemergence herbicides. By increase spray deposits of the spray material, this new product provides better coverage and adhesion to soil particles keeping the herbicide in the upper portion of the soil for maximum weed control. Studies incorporating Cohesion with Acetochlor and Pendimethalin have shown enhanced control 48 DAT. The recommended rate is 8oz per acre of Cohesion. This is such a cost effective product, we are going to be recommending it on all of our growers in 2026. For additional information on Cohesion, check out the product tech sheet on our site.
We hope the information within this short blog was helpful. We are currently utilizing these practices and products with our growers. For additional information on products found within our site, check out some of our other blog posts.
Thanks for reading this blog. -Brian
jOhnson, bill & Zimmer, marcelo. “Which Residual Herbicide Should I Use for Waterhemp Control in Soybeans?” 27 Jan. 2022,
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This blog may contain pesticide recommendations that are subject to change at any
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