With tornadoes touching down in January and ground-baking drought conditions occurring in April and May, it’s safe to say the most accurate weather prediction is that the weather is getting harder to predict. That’s why soybean growers need to be ready to zig when the weather zags — especially when it comes to weed control.

Preemergence herbicide applications are particularly sensitive to weather; too little rain, and the herbicide might fail to incorporate or activate; too much, and the herbicide may lose efficacy or fall victim to runoff. These scenarios can leave growers exposed to early season weed pressure that can cause irreversible yield losses.

“The fact is most preemergence herbicides need some amount of rain to help water them into the soil and activate them,” says Scott Pringnitz, market development specialist, Corteva Agriscience. “How much is enough, and what’s the optimal timing? That all depends on the products you’ve applied, your soil type, your temperatures, the weed profile in a given field and a ton of other variables.”

Pringnitz says a smart strategy for weed control in variable weather conditions starts with a preemergence program that uses a combination of residual herbicides with different modes of action.

An effective preemergence herbicide program can help widen spray windows later in the season, giving producers the flexibility to handle mid- and late-season weed pressure. Photo submitted by Corteva Agriscience.

“Using a good preemergence combination is one of the best ways to mitigate the risks of no, low or too much rainfall,” Pringnitz says. “Plus, an effective preemergence program helps widen spray windows later in the season, giving farmers that much more flexibility when dealing with variable weather.”

Pringnitz says a combination of herbicides with multiple modes of action not only helps reduce the risks associated with variable weather but also can help prevent herbicide resistance. Sonic® herbicide, for example, uses two modes of action to provide preemergence control of tough broadleaf weeds while helping protect against resistance. Trivence® herbicide offers three modes of action and gives effective burndown control and extended residual activity on tough broadleaf weeds.

Once the preemergence application has been made, producers should closely monitor newly planted fields for weed escapes. If two weeks pass since the preemergence application and either no rainfall or excessive rainfall has occurred, Pringnitz says, producers should be ready to make a postemergence application. A product such as EverpreX® herbicide provides an effective layer of residual control and can be tank-mixed with Enlist One^® herbicide to manage weeds in Enlist E3^® soybeans. For the 2025 growing season, farmers will have a new weed control solution with Enversa^™ herbicide, which will drive to the soil to create a residual barrier against weeds. 

Pringnitz says in addition to a well-planned, well-executed herbicide program, smart variety selection can help reduce the risks of yield loss from weather and weed pressure.

“Heat stress and late-season weed pressure can really derail the train,” he says, “and can be significant factors in yield losses. Planting later-maturing varieties can help reduce those risks.”

With many climate models predicting warmer, drier weather throughout much of the U.S. soybean-growing area, having a solid, season-long plan for weed control can go a long way toward ensuring growers achieve the highest possible yield. Contact your local Corteva Agriscience representative or visit Corteva.us for help planning your herbicide program.

_{™ ® Trademarks of Corteva Agriscience and its affiliated companies. The transgenic soybean event in Enlist E3® soybeans is jointly developed and owned by Corteva Agriscience and M.S. Technologies L.L.C. Enlist Duo® and Enlist One® herbicides are not registered for sale or use in all states or counties. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your area. Enlist Duo and Enlist One herbicides are the only 2,4-D products authorized for use with Enlist® crops. Consult Enlist® herbicide labels for weed species controlled. EverpreX®, Enversa™, Sonic® and Trivence® are not registered for sale or use in all states. Enversa is not available for sale, distribution or use in Nassau and Suffolk counties in the state of New York. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions. ©2024 Corteva.  19050  BR (03/24)  CAAG4SOYB060}