Corn rootworm control accounts for the largest agricultural use of insectides in Iowa. Most chemicals are applied in granular form, which makes them accessible to wildlife. Because these chemicals can be toxic, "softer" insecticides would be desirable from an environmental standpoint. Monoterpenoids, one type of softer insecticide, are natural products (constituents of essential oils from mints, cedar, pine, and citrus) that biodegrade fully and rapidly