In follow up to our recent post on Northern corn leaf blight, we want to provide information about another common corn disease that is among the top yield-reducing diseases in the U.S.: gray leaf spot. Gray leaf spot is a troublesome foliar disease for several reasons:

• The gray leaf spot pathogen overwinters in crop residue. This means that no-till operations in fields with a history of gray leaf spot are at higher risk of infection.
• It is a foliar disease that compromises the integrity of corn leaves, reducing the plant’s ability to photosynthesize. University of Nebraska-Lincoln Extension research explains that reduced photosynthesis limits the amount of kernels produced by each ear.
• When the corn plant can’t draw enough energy from the sun for grain-fill, starches are drawn from the stalks, leading to increased potential for lodging.

Management tips:

As with other foliar diseases, like Northern corn leaf blight, there are several steps you can take and tools you can use to effectively manage gray leaf spot and maximize yield and ROI.

• Know the signs and symptoms of gray leaf spot. Gray leaf spot forms thin rectangular lesions along the leaf veins that combine together into longer lesions as the disease progresses.
• Plant tolerant hybrids/inbreds. The University of Nebraska-Lincoln Extension also explains there are no current corn hybrids or inbreds that have complete resistance to gray leaf spot, but some hybrids are more tolerant than others and will do well in moderate to high disease pressure.
• The University of Minnesota Extension recommends employing conventional tillage and crop rotation practices, as appropriate, to help reduce the amount of pathogen buildup in your fields.
• When needed, use a foliar fungicide with proven activity against gray leaf spot.

When a fungicide is needed, Syngenta recommends Trivapro® fungicide. Trivapro provides both preventive and curative activity against several yield-robbing corn diseases, including gray leaf spot. Additionally, it has the longest-lasting residual disease control on the market to help you maximize yield, ROI and profit potential in 2018.

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