Submitted to: Journal of Entomological Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 4, 1998
Publication Date: N/A
Interpretive Summary: Corn rootworms are the most destructive insect pests of corn crops in the United States. Expenses incurred by farmers, due to losses and control costs on 25-30 million acres, total about $1 billion annually. Insecticides are generally applied routinely and often unnecessarily, imposing health risks to growers, livestock, and wildlife. There has been a major effort to replace these conventional insecticides with baits laced with ultra-low doses of insecticides. The replacement reduces the amount of insecticide introduced into the environment. Presented here is a new, environmentally friendly, water based bait. This bait consists of a watermelon extract, an FDA approved red dye, and starch. The watermelon extract induces the adult rootworms to feed compulsively on the bait. The red dye kills the insects best in the presence of bright sunlight. Potential customers are industries that make, and growers that apply, pesticides for the control of corn rootworm.
Laboratory and field-cage experiments were conducted to evaluate the efficacy of a new water-soluble bait for control of adult corn rootworms. The bait was composed of a water-soluble feeding stimulant (FS) from a crude extract of a bitter mutant of Hawkesbury watermelon (BHW), Citrullus vulgaris Schrad; a dye toxin (phloxine B: D & C Red Dye No. 28); and a modified food starch (Mira Sperse 626). In the laboratory, southern corn rootworms (SCR),Diabrotica undecimpunctata howardi Barber were exposed to separate bait components and combinations thereof. Eighty percent of SCR exposed to the complete bait formulation died within 24 h. SCR mortality increased with increasing concentrations of dye used and increasing light intensity. The feeding stimulant plus the dye reduced the time to kill SCR. The complete bait, was most active in sunlight, killing more than 90% SCR adults in 1 h. Under fluorescent lights, time to kill 90% SCR adults was 48 h. In field cages, using corn plants treated with dye and FS bait formulation, numbers of live western corn rootworm (WCR), D. virgirfera virgirfera LeConte adults were reduced by over 80% compared to the untreated control. This new water soluble toxic bait appears suitable for testing in the field on a larger scale as a component in the IPM of corn rootworm pests.