Iowa expert on rootworms helps Europeans

A pesky bug that can heavily damage a corn crop is being well-managed in Iowa, but it’s wiping out fields in Europe. Iowa State University entomology professor Jon Tollefson has just returned from two weeks overseas, where he shared his expertise with European agricultural officials in how to fight corn rootworms, which are gobbling their way across that continent. The rootworms were first discovered in Serbia in 1992 and have since spread across much of Central Europe and into Italy, Austria and France. Parts of the continent are seeing such heavy infestations, it’s causing economic damage. Since Tollefson is considered an expert on the corn rootworm, Croatia asked for him by name, to help develop management research and extension programs for the insect. Tollefson says he did meet with some farmers, but his primary goal was to help Croatian ag officials understand the complex problems involved in battling the bug.In fighting the rootworm in Iowa, most farmers use insecticides, while some grow genetically-engineered crops that are resistent to or that kill the invading insects. Tollefson says neither of those options are good in Croatia: insecticides are too expensive and the G-M-O seeds are illegal in virtually all of Europe. He says there is another prospect for the Europeans to control the pest.He says crop rotation may be a viable alternative to be the mainstay for managing the insect, because of the bug’s life cycle. It generally only hits fields where corn is planted year after year and not those where other crops are rotated in. The rootworm lays its eggs each fall in the corn and the larvae hatch and feed on growing corn plants in the spring. A crop of anything else — from sunflowers to sugar beets or soybeans — means the rootworms starve and die.