Eliminating weed competition is critical to corn development during it’s initial growth stages. Weed pressure during that growth period can decrease yield significantly depending on the intensity and duration of that pressure. Timing your herbicide application properly can ease back weed pressure while keeping your crop from being damaged.

Depending on the herbicide you use, that decision to spray has a few qualifiers attached to it. The main qualifier being the restrictions on spraying based on leaf staging. Most herbicides won’t allow you to spray past the four leaf stage.


In this episode of the Corn School, Mike Cowbrough of OMAFRA takes viewers through the definition of the four leaf stage, how to properly gauge weed pressure and why a 3 to 5 day window is so critical in spraying.

If you cannot see the embedded video below click here.

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