Besides aflatoxins, other examples of toxins produced in moldy ears are deoxynivalenol (vomitoxin), zearalenone and fumonisin.
But, just because the corn may have ear mold, not all ear molds are associated with mycotoxin contamination, Paul cautions.
"Don't just abandon your field if it looks dark and moldy," he says. "Some opportunistic fungi grow on the husk without affecting the grain.
"These typically leave the ear looking dark and discolored, but when the husk is removed, the grain looks healthy and normal. If you see the ear looking ugly, don't assume you do or don't have ear rot. Pull the husk back and take a look at what is going on."
To know for sure, Paul said it's best to pull multiple ears from around the field to send in to a lab for testing.
"Growers are concerned when they see these black ears, but if the mold is an opportunistic fungi, the ear could be still good on the inside," he said.
Samples from suspect fields should be sent to an approved laboratory to determine whether aflatoxins or other toxins are present and whether they exceed thresholds established by the U.S. Food and Drug Administration.
More information on aflatoxin testing and FDA thresholds is available here and here.