Keep corn diseases at bay in 2022

NORTH JUDSON, Ind. — To manage diseases that can overwinter in fields, growers should make management plans for next season now — starting with hybrid selections.

Diseases such as gray leaf spot, northern corn leaf blight and tar spot were found in fields this year.

“We can do a number of things to manage these diseases in 2022,” said Mary Gumz, Pioneer agronomy manager. “No. 1, pick the right hybrid. The right hybrid will have tolerance to the disease, as well as overall foliar disease health. No. 2, start planning for fungicide use. Weather will favor these diseases, so have a plan in place before pressure gets too severe.”

Diseases can overwinter in infected crop residue, allowing inoculum to build up from year to year in fields. Disease spores are spread by rain splash and air currents to leaves of crop plants, where primary infections are produced.

Secondary spread occurs from plant to plant and field to field as spores are carried long distances by the wind. Infections generally begin on lower leaves and then progress up the plant.

Because these diseases overwinter in corn debris, production practices, such as tillage and crop rotation, can reduce the amount of surface corn residue and decrease the amount of primary inoculum.

In severe cases of disease infestation, multiple years of crop rotation away from corn may be necessary.