Drought leads to moldy growth in corn

WEST LAFAYETTE, Ind. (WLFI) - State corn farmers are experiencing high amounts of a specific mold in their fields this year after the season-long drought hindered corn pollination.

The mold is called smut.

No – not smut as in inappropriate literature – smut as in a grey, moldy growth on corn ears.

It’s present in Indiana cornfields every year, but it’s never been seen at 2012’s high level.

"Researchers have debated about what conditions favor smut development, but it is reported that poor pollination, dry weather and warm temperatures can increase smut development," said Kiersten Wise, Purdue Extension plant pathologist. "That certainly fits the conditions experienced during the majority of the 2012 growing season."

According to Wise, smut is caused by the fungus Ustilago maydis, which can remain alive during several winters in the crop residue and soil.

Smut usually infects stressed leaf tissues, typically through wounds caused by hail or insects.

Smut also gets to corn ear kernels through silks. Tassels and nodes can also be infected.

"Once tissue is infected, the fungus causes plant cells to divide and expand, which results in the diagnostic white 'galls' that we see with smut," Wise said. "Mature galls are filled with dark spores that may break open and leave a powdery residue on surrounding tissue."

Now, even with the unusually high incidence of smut this year, it won’t affect the corn yield.

And while fungicides aren’t very effective against the disease, there are other management options in the off-season.

"Management options include tillage and rotation to reduce the amount of debris that harbors the fungus, promoting proper corn fertilization and limiting wounding of corn by mechanical equipment," Wise said.

Smut is not toxic, and it is actually usually grown to be consumed as a delicacy. But, Wise says people should not harvest and eating the galls from a cornfield, especially once they start to turn black.

Wise also said corn growers and farm crews with lung ailments or mold allergies should be exceptionally careful this harvest season.