Corn School: Weather stress can fuel northern corn leaf blight


While it’s important to stay current on new and emerging diseases of the corn crop, it’s still important to keep tabs on the old standbys, such as northern corn leaf blight.

“We know the weather’s been favourable for diseases, and we get lots of calls on that,” says Alberta Tenuta, plant pathologist at OMAFRA. There’s a long history of northern corn leaf blight, and Tenuta says that it’s here, it’s always going to be here, and don’t forget about it, year over year.

In this episode of RealAgriculture’s Corn School, Tenuta is joined by Bernard Tobin at the Ridgetown campus fungicide trial, to check out the symptoms of northern corn leaf blight, to talk about how fast the disease can advance, and the ideal weather for this fungus to progress.

Symptoms range from elongated cigar-shaped lesions, to much larger lesions that expand across the leaf. Many times, those lesions show up when the leaf has curled and the moisture stays the longest, says Tenuta.

Humid conditions, as well as conditions that stress the plant, are ideal for the fungus to move in and advance, and Tenuta says that he’s seen anywhere of up to 50 to 60 bushel yield hit, or more.

“For most growers, you’re looking at a five, to 10 to 15 bushel yield hit, that’s pretty significant, especially with good corn prices,” says Tenuta, adding to remember hybrid ratings and that different blight races will affect the hybrids differently.

There are a lot of fungicide options for control out there, and the timing is at tassel, says Tenuta.

Never has anyone been so excited to see symptoms of a disease in the field, but Tenuta is; see the video below for more on managing the risk of Northern corn leaf blight, and more:

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Corn School (view all)Season 10 (2021) Episode 15

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