South Africa: The Moth That Eats Corn Crops

Thought moths were a threat to your clothes? They can devastate corn crops, too, and do in eastern and southern Africa. I got my first look at busseola fusca on Friday after hearing about ever since I arrived in Africa to look at the challenges facing farmers here and the potential for biotechnology to increase food production.

This moth is the key reason that biotechnology has taken off with farmers in South Africa in recent years in much the same it did with farmers in the United States. Today, about two-thirds of South Africa's corn production is genetically modified, primarily to attack this moth larva, known to African farmers as the stalk borer. The moth is a pest elsewhere, but so far South Africa is the only sub-Saharan country that permits the production of genetically modified food crops.

The moths lay their eggs in corn stalks, and when the larvae hatch they start tunneling, or boring, their way through the plant, choking off nutrients that need to get to the rest of the plant. The larvae also can damage the ear, reducing the value of the kernels and allowing diseases to enter.

I traveled to Pioneer Hi-Bred's research station east of Pretoria with the manager of the Des Moines-based company's South Africa business, Willem Engelbrecht. I told Willem I'd like to see an example of this pest I'd been hearing so much about, so he sent a staff member off looking for a stalk of non-GMO corn around the station that had been attacked by the larvae. It didn't take long for one to be found. Willem sliced open the stalk and inside was at least one larva that, sure enough, was boring its way up the plant. (Willem shows the pest and its damage in the photo.)

While the pest is similar to borers that attack corn in the United States, the genes that attack the U.S. version won't necessarily work against the African borer.

Pioneer, for example, has licensed a gene from Monsanto Co. to produce its borer-resistant corn seed in South Africa. Monsanto has an improved version that it's bringing to Africa and hopes to begin testing soon in Kenya. Monsanto has refused to license the new version to its arch-competitor, Pioneer.

It's worth watching what happens to these products, because they could be the key that opens the door to genetically modified crops in countries beyond South Africa.