Mold sprouting, hiding in corn fields

Oct. 4, 2022

If your corn is still in the field, it’s worth checking to see how much of it might be infected with ear mold so you can mark the worst fields for early harvest. Handling grain with mold issues may require changes in drying and storing protocols. At the same time, keep a sharp eye out for sprouting and insect damage.

“We realized there might be an issue when we inspected the Corn Watch field in central Indiana in early September,” says Dave Nanda, director of genetics for Seed Genetics Direct. “We did yield checks, and more ears than normal for that time of year were showing signs of mold.”

Since then, reports of agronomists, seed industry reps and farmers finding ear molds and sprouting or other quality issues have increased. Nanda asked an associate to return to the Corn Watch ’22 field during the week of Sept. 19 and check for ear molds in two random locations.

In each case, 50 consecutive corn ears were husked and the ears with evidence of mold growth were counted. Mold was more severe on some ears than others. At one location, 42 percent of the selected ears were infected and on darker soil where plants were still green, 64 percent of ears were infected. That’s an average of 53 percent.

Two other fields were checked. At the Throckmorton Purdue Agricultural Center near Romney, Ind., corn in an Indiana Prairie Farmer/Purdue University trial was examined. An average of 21 percent of all ears husked showed evidence of mold. At a field operated by the Franklin FFA Alumni in Johnson County, Ind., the average percent infected was 16 percent.

Types of mold discovered have not yet been confirmed. Nanda suspects the Corn Watch ‘22 field has cases of both fusarium and gibberella. These molds can produce mycotoxins, most notably vomitoxin. However, just because mold exists doesn’t guarantee it’s producing a mycotoxin. Aspergillus, a greenish mold often seen after very dry weather, can produce aflatoxin. No aspergillus fungus has yet been confirmed on any of the ears inspected.

The Corn Watch ’22 field is sponsored by Seed Genetics Direct. Reports on the field’s progress are provided all season by Tom Beckman of Indiana and Ohio Prairie Farmer.