Volunteer Corn Becoming a Growing Concern in Area Soybean Fields

CELINA — Drivers traveling through Mercer County may notice something unusual growing above some soybean fields: scattered stalks of corn.

Ryan McMichael with Mercer County OSU Extension said the plants are known as “volunteer corn.” Despite the friendly-sounding name, farmers consider the corn a weed when it grows in a field where it was not intentionally planted.

Volunteer corn develops from kernels or ears left behind during the previous year’s harvest. Corn that does not make it into the combine can fall to the ground, remain in the soil and emerge during the following growing season.

McMichael said OSU Extension’s annual weed escape survey has shown volunteer corn becoming a more frequent problem in soybean fields.

Dry conditions during the previous growing season may have contributed to what farmers are seeing this year. Corn that dries quickly can break apart or fall from the stalk more easily during harvest, leaving additional kernels behind to grow the following spring.

Controlling volunteer corn can also be complicated. Much of the corn planted locally is designed to tolerate certain herbicides. When that corn later emerges in a soybean field, the herbicide being used to control other weeds may not kill it.

Farmers may need to add another herbicide or make an additional pass through the field. McMichael encouraged producers to consult OSU Extension resources, the weed control guide or a local agronomist before deciding how to manage the problem.

Although the corn may look healthy, it competes with soybeans for water, sunlight and nutrients. McMichael said any plant growing where it was not intended can be considered a weed.

Volunteer corn is not the only concern appearing in local fields. McMichael said producers are also beginning to see troublesome weeds such as waterhemp and giant ragweed. Changes to herbicide programs and residual products that did not remain effective as long as expected may have allowed some weeds to emerge.

Despite those challenges, McMichael said the overall condition of the area’s corn and soybean crops appears encouraging. Timely rainfall has helped both crops continue developing, with additional moisture especially important during corn grain fill and soybean pod development.

Producers still considering weed-control applications were reminded to read and follow product labels carefully, particularly once crops have entered the flowering stages.

McMichael also discussed choosing weed-control products for lawns, gardens and landscaping. He said homeowners should understand whether a product is selective—designed to target certain plants—or non-selective, meaning it may damage nearly any plant it contacts.

Recent rain and humidity have also created conditions favorable for plant diseases, including powdery mildew on lilacs and other plants. McMichael said some diseases, including maple tar spot, are primarily cosmetic and may not justify a chemical treatment. Correctly identifying the problem is important before deciding how to respond.

Residents and producers needing help identifying a weed, crop issue or plant disease may contact the Mercer County OSU Extension office. The office can also provide educational materials and information about licensed pesticide applicators serving the county.