Insight •  2023-06-15

How to overcome problem weeds in July

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Your last window to control weeds is quickly closing. By July, most corn and soybean crops are beginning to canopy, and you’re off the hook for weed control. But there’s still a chance to manage late escapes, problem perennials like thistles, or later emerging annuals like common waterhemp. If you’re ready to make one last pass to take care of these weeds, we’ve got a few reminders to help you achieve success and reduce the risk of crop injury.

Crop stage and product options

Understanding weed control options based on crop staging is the most important consideration for late season weed control. The first question to ask is, ‘is it safe to spray’? At this point in the growing season, you need to balance the benefits of weed control with the risk of crop injury.

Soybeans: Many herbicides, including Classic and FirstRate must be applied before the onset of flowering. Once soybeans start to flower (typically in July), the risk of crop injury increases. One of the advantages of using the Enlist™ weed control system is that Enlist herbicides can be safely applied up to the R2 stage of soybean growth. This added bonus extends the window of weed control for soybeans, helping you achieve cleaner fields and higher quality soybeans.

Corn: Herbicide options for corn extend to later stages. Accent™ IS and Lontrel™ XC are both effective options that can be applied up to V6 or the 8-leaf stage. Lontrel XC is especially effective against thistles.


Read and follow product labels carefully to confirm just how late in the season and crop growth stage you can safely make herbicide applications. And don’t forget about crop susceptibility to injury and account for wind speeds to reduce injury to susceptible crops from drift.

For advanced crops, make sure to keep boom height at the correct level relative to the top of the crop canopy to ensure the right rate is applied, and remember to keep water volumes at optimal levels, usually a minimum of 15 gal/ac.

Considering late season weed control, but unsure about your herbicide options? Consult your trusted agronomist, retailer, or local Corteva Agriscience™ Territory Manager for advice on products, rates and crop growth stages.