Climate Change Fanning Humungous Fungus Problem for Farmers

It’ll be warmer, they said.
It’ll be greener, they said.

We’ll grow more food, they said.

Bayer Crop Science:
Aflatoxin is a toxic substance produced by the fungi Aspergillus flavus and Aspergillus parasiticus in agricultural crops such as corn kernels, cotton seeds, and tree nuts. Aflatoxin in corn must be monitored closely as it is highly toxic to many animals and can be fatal to livestock. Aflatoxin can infect corn across the Midwest and Southern United States, especially if corn is under insect or drought stress. Identifying the fungus that produces aflatoxin, testing grain for contamination, and managing contaminated grain can help control aflatoxin in corn.

Michigan State University:

 A toxin produced by a fungus in corn will increase over the next few years because of global warming, according to a Michigan State University study.

From 2031-40, over 89.5% of the counties in 15 states will experience a rise in aflatoxin levels, according to the study in the Environmental Research Letters.

Corn is mega-business in Michigan where the value of the 2021 crop of corn used for grain topped $1.85 billion, U.S. Department of Agriculture statistics show. 

That year, farmers in three counties planted at least 100,000 acres of corn: Sanilac (108,000), Lenawee (107,000) and Huron (100,000). Overall, farmers in the state planted 2.35 million acres, according to the department.

Aflatoxin is a toxin produced by two fungi that can cause cancer. They typically grow near food crops and enter the corn through pollen tubes or through damage caused by insects. 

Aflatoxins are the most prevalent natural liver carcinogen. Chronic levels of exposure can hinder child growth and nutrition, the study said. 

The primary culprit? Climate change. 

The two fungi that produce aflatoxins grow more readily in warm, dry climates. That’s why they’re most prevalent in Southern corn crops, the study said. 

As climate change worsens and air becomes warmer and dryer, more corn crops will become contaminated with aflatoxins, it said. That will likely decrease the amount of healthy, clean corn available for those who rely on it for dietary and economic purposes. 

How we collectively manage the problem over the coming years is a primary concern for agricultural scientists like David Hennessy, a production economist at Iowa State University who worked on the study while he was at Michigan State University. 

“Part of the reason for writing this paper is to alert corn growers in the Midwest that this problem may be on the way to you,” Hennessy said. 

The Midwest is likely to see the greatest rise in aflatoxin accumulation because its current climate is less dry and less warm than in the Southern U.S. The hotter the air in the Midwest becomes, the more likely these fungi are to grow there. 

Another problem presented by the increase in aflatoxins is how it impacts animals. 

If livestock like cows and pigs eat contaminated corn, farm production will decrease and less animal products will be available for consumption, Hennessy said.

It’s a problem issue primarily in the U.S. because the type of corn most prone to aflatoxin contamination is fed to animals here, Hennessy said. 

“It’s a problem because animals fed corn that is afflicted with aflatoxins won’t perform very well,” Hennessy said. “They’ll have reduced growth rates and so on. So there are limits on how much aflatoxin can be in corn fed to hogs, cattle and poultry.”

Aflatoxins are regulated for both human and animal by the Food and Drug Administration, according to the study. Not many corn producers now experience great loss due to aflatoxin contamination, especially in the Midwestern Corn Belt and Northern states. 

If the study’s projection is accurate, the risk of contamination will increase so significantly that clean corn may be in short supply. That could quickly become a global issue, as the U.S. Corn Belt is a major supplier of the crop across the world, Hennessy said. 

For people in other countries who rely heavily on corn for food, that could adversely impact their way of life. 

Food security would decrease as the Corn Belt sees an uptick in aflatoxin production, causing a ripple effect in some national economies, Hennessy said. 

MSU student and climate activist Sarah Bill noted that an increased demand for clean corn could change how its market operates. 

“If there’s only so much [corn] that doesn’t have aflatoxin in it, then people are going to buy it all and the price might increase,” Bill said.