Corn School: Zoom in when scouting for gibberella

As combines push through the Ontario corn crop, growers are being advised to focus their first harvest efforts on fields where gibberella fungus could produce higher levels of deoxynivalenol (DON) in the grain.

On this episode of the RealAgriculture Corn School, agronomist Peter Johnson shares tips for identifying fields at higher risk for gibberella and what growers should look for as they scout and assess these fields.

Johnson says growers need to know their hybrids and whether the genetics offers a strong defence against gibberella. In the video, he notes that the 2023 DON survey does show elevated levels of DON in certain areas of the province, but overall the challenge is manageable if growers act quickly to harvest high-risk fields.

In the video, Johnson scouts a fields where the number of significantly-infected cobs are relatively small — one in 20 cobs— but he notes that gibberella fungus is present on many ears and levels could grow rapidly. When he zooms in on what appears to be a relatively clean cob he sees evidence of the fungus growing down between the kernels of the cob. (Story continues after the video.)

“If we get this out of the field immediately, then probably the level of DON will be manageable,” says Johnson. But if growers wait and allow the fungus to continue to grow they could face elevated DON levels and challenges when marketing the crop.

Johnson recommends that growers scout suspect fields and pay special attention to fields planted to continuous corn and any field that may have endured stress during the growing season. That includes fields that were either very wet or very dry through pollination.

See Related: Fine tuning the combine to reduce DON levels

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