Corn School: Diplodia leaf streak heading north

Corn growers in the mid-south and Midwest U.S. are being asked to take a closer look at diseased corn leaves as re-emerging diplodia leaf streak pushes into major corn growing states.

The disease looks very similar to northern corn leaf blight (NCLB), a leaf disease Canadian growers typically identify based on its characteristic cigar-shaped lesions. Earlier this month at the SouthWest Agricultural Conference, University of Kentucky pathologist Kiersten Wise offered tips on how to distinguish diplodia from NCLB. She noted that the key distinction is diplodia lesions are more rounded and look like pepper scattered on the corn leaf.

On this episode of RealAgriculture’s Corn School, Wise tells Bernard Tobin that diplodia is not new to the southern U.S. What has changed is the disease is now moving north and has been identified in Midwest cornfields. Also concerning are reports from growers that the disease is now causing yield loss in their fields — something researchers have seen little evidence of in the past.

Wise notes that there are currently no fungicides registered for control of diplodia the U.S. She and her colleagues are now working with companies to understand hybrid resistance and what production practices might influence the disease.

Will diplodia make it to Canadian cornfields? Wise believes warmer weather in the Midwest and climate change impacts are likely influencing the disease’s northern migration, but it’s probably too early yet to sound the alarm bell for growers north of the border.

Click here for more Corn School episodes.

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