Evaluating Insecticides for Corn Rootworm Larval Control Using a New Rating Scale

Researchers estimate that com rootworms, Diabrotica virgifera virgifera LeConte and D. barberi Smith and Lawrence, cost U.S. com growers one billion dollars annually in chemical control costs and crop losses (Metcalf 1986). Between 50 and 60% of the total U.S. com acreage has some chemical control applied for com rootworms (Metcalf 1986). In Iowa, 22% of all com is treated with an insecticide for com rootworm control today (Hartzler et al. 1997)