Controlling Corn Rootworms: Old Technology Versus New
As is typical with corn rootworms, densities during 1997 varied dramatically throughout the Corn Belt and even within states. Iowa and some of the states east were abundantly blessed with corn rootworms. To the north and west of Iowa, the insect was less abundant, even hard to find at times. Within states where numbers were generally high, there were pockets of very high numbers spread among more typical densities. The result was that there were numerous reports of poor soil insecticide performance, usually clumped within areas. In Iowa I was in a "hot spot" east of Maquoketa where a number of the registered products did not provide adequate root protection. Illinois reported that, at two of their research sites, none of the registered chemicals satisfactorily protected roots from larval feeding. A summary of the Iowa State University soil insecticide data, updated to include the 1997 results, will be distributed at the breakout session.