Aflatoxin can ruin a corn harvest as surely as a hail storm or a plague of locusts. Contamination may render the crop unmarketable and label production areas as undesirable supply sources.

Some Texas farmers understand all too well the stigma of aflatoxin and have endured the ignominy and have lost prime markets because of a reputation for too frequent instances of aflatoxin contamination.

They often feel at a loss, vulnerable to forces beyond their control, such as drought and heat stress. No curative treatment has been discovered for the fungus, but corn farmers do have options to decrease the potential for infection.

It takes a combination of plant host resistance, insect control, cultural practices, and biological treatments—a relatively new option—says Texas AgriLife Extension pathologist Tom Isakeit, who works out of the San Angelo Research and Extension Center.

“We need to use an integrated approach,” Isakeit told a farmer and industry audience at the recent Texas Plant Protection Association annual meeting in College Station.

He said plant resistance may play a somewhat minor role for now. “We have no resistance to the fungus,” he said, “but resistance to insect pests may be helpful. But insect damage is not the sole reason for aflatoxin contamination.”

He said variety selection remains important, however. A tight husk, for instance, helps keep the contaminant out. “An ear that turns down is also an advantage, as is a hard endosperm. The fungus enters injured seed.

“Trials have shown a small beneficial effect from Bt genes. But do not rely on transgenic hybrids to control mycotoxins,” he said.

He said some hybrids appear to be “more prone to contamination.”

Cultural practices are also important. “Farmers should produce the best crop possible,” Isakeit said. He recommends producers break hardpans, use minimum tillage to conserve moisture, plant during the optimum planting window, maintain optimum nitrogen and control insects and weeds.

Biological controls recently have produced encouraging results. “We have atoxic strains of aspergillus that outcompetes the toxic strain,” Isakeit said. “We have to get it established first.”