Corn leaf infected with gray leaf spot

Year after year, Northern corn leaf blight (NCLB) and gray leaf spot (GLS) are problem diseases for corn growers, and in recent years, a newly identified disease – tar spot – has been on the rise, causing increased concern. Although found in Midwest states, tar spot was initially identified in PA in 2020. This disease can cause low test weight, reduced kernel fill and poor silage quality, ultimately leading to a severe loss in yield potential when corn is left untreated.

Agronomy Service Representative Craig Austin discusses how to identify each of these 3 diseases as he walks through a fungicide trial at the Mt. Joy, PA, Grow More™ Experience site.

Austin points out a few key identifiers for each corn disease:

• GLS: Small, rectangular lesions that are bound between veins on the leaf, which may elongate over time and ultimately take over the whole leaf.
• NCLB: Long, cigar-shaped lesions that are tan or gray in color, often appearing parallel to leaf margins.
• Tar spot: Small, raised black spots that are circular or oval in shape and do not rub off when touched.

Because NCLB, GLS and tar spot can be easily missed when present at low levels, it’s important to apply a preventive fungicide like Miravis® Neo fungicide or Trivapro® fungicide to stay a step ahead before disease leads to potentially widespread yield loss.

To learn more, visit BoostYourBushels.com and see how Miravis Neo performed against competitors and untreated acres in local and regional trials. Or, use our yield calculator to find out how many more bushels you could save with Trivapro.

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