Late planted corn may trigger more aflatoxin

Weird weather, from too dry to too wet to downright deadly from a series of tornadoes that left debris spread across thousands of acres of North Carolina farmland, has delayed corn planting statewide.

Planting a couple weeks later than ideal likely won’t have much impact on the final state yield of corn, says North Carolina State Corn Specialist Ron Heiniger. However, it will put corn at much higher risk of aflatoxin in the crop and can significantly impact quality and price of the 2011 crop.

The veteran North Carolina State University researcher says work he’s conducted recently with a new product, Aflaguard, offers great hope for farmers who were forced to plant corn late this year.

Avoiding economic shortfall associated with aflatoxin-infested corn, he says, is important to take advantage of today’s high grain prices to growers.

Aflatoxin is a toxic metabolite produced by the fungi, Aspergillus flavus and A. parasiticus. Aspergillus spores can infect corn ears and kernels through silk channels, wounds caused by birds, hail and a variety of ear-feeding insects or through other openings in the seedcoat such as silk cuts and stress cracks.

Hot, dry weather is a well known trigger for Aflatoxin development. Late planting exposes corn plants to more prolonged periods of heat and dry weather in the upper Southeast.

Aflatoxin is more likely to occur in the field in years characterized by high temperatures and drought, and may also occur in grain not properly dried or stored.

Hail damage is another source of stress more typically associated with corn that is exposed longer to mid-to-late summer heat. Corn ears damaged by hail are prone to develop fusarium ear rot and aspergillus ear rot.