Canny Corn Beetles Get to the Root of the Problem

Darwin would have been proud of the corn rootworm. The beetle has proved it can adapt, survive and thrive despite every strategy devised by man to eliminate it.

This major pest of maize is playing havoc across the American corn belt. The traditional method of control is to rotate crops, switching maize and soya every other year. The idea was that the rootworms would starve after hatching in a soya bean field the next year.

But rootworms apparently catch on quickly, and adult beetles were seen flying off and seeking soya bean fields to lay their eggs, having worked out that maize would be planted there the following spring to feed the baby worms.

The northern cousin of the western corn rootworm that also needs a new crop to feed its young came up with another idea. Instead of hatching the following spring its eggs lay dormant for an extra year, catching the crop as it came back under the maize-soya-maize rotation.

To make matters worse, according to the Statutory Conservation Agencies Biotechnology Bulletin, western rootworms have developed resistance to insecticides applied to kill them.