Skip to main content
ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #243134
Title: Synthetic feeding stimulants enhance insecticide activity against western corn rootworm larvae, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae)

Author
item BERNKLAU, ELISA - Colorado State University
item BJOSTAD, LOUIS - Colorad0 State University
item Hibbard, Bruce

Submitted to: Journal of Applied Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2009
Publication Date: 1/15/2011
Citation: Bernklau, E.J., Bjostad, L.B., Hibbard, B.E. 2011. Synthetic feeding stimulants enhance insecticide activity against western corn rootworm larvae, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). Journal of Applied Entomology. 135:47-54.

Interpretive Summary: The western corn rootworm (WCR) is a major insect pest in continuous corn production. By feeding on corn roots, WCR causes economic losses due to decreased nutrient uptake and plant lodging, both resulting in yield loss. Currently, insecticides and transgenic corn are only available options for its control under continuous corn production. Feeding stimulants for WCR were recently isolated from maize and identified. Dilutions of two WCR insecticides (thiamethoxam and tefluthrin) were tested in bioassays alone and in conjunction with the WCR feeding stimulant blend. Larvae were placed on insecticide-treated filter paper disks in an arena that allowed them to leave the treated area at will. The addition of a synthetic feeding stimulant blend improved the efficacy of the insecticide thiamethoxam against neonate western corn rootworm larvae as much as 10,000 fold. Larvae fed readily on disks treated with tefluthrin when the feeding stimulants were added, but the feeding stimulant blend did not affect the activity of tefluthrin insecticide at any concentration tested. The substantial enhancement of the effectiveness of thiamethoxam with feeding stimulants may lead to an additional management option for maize growers.

Technical Abstract: In behavioral bioassays, the addition of a synthetic feeding stimulant blend improved the efficacy of the insecticide thiamethoxam against neonate western corn rootworm, Diabrotica virgifera virgifera LeConte, larvae. In 4-h bioassays, the concentration of thiamethoxam required for 50% mortality (LC50) was 568 pg/ml for the insecticide alone, but was reduced to 0.045 pg/ml when the synthetic feeding stimulant blend was added (a 10,000-fold difference). Dilutions of thiamethoxam and tefluthrin (ranging from 0 pg/ml to 10 µg/ml) were tested in behavioral bioassays alone and in conjunction with a feeding stimulant blend containing 30:4:4:1 mg/ml glucose:fructose:sucrose:linoleic acid. Larvae were placed on insecticide-treated filter paper disks in an arena that allowed them to leave the treated area at will. In 30-min bioassays, and in 4-h bioassays, significantly more larvae fed on thiamethoxam-treated disks when the feeding stimulants were present for every concentration of insecticide tested. Larvae fed readily on disks treated with tefluthrin when the feeding stimulants were added, but the feeding stimulant blend did not affect the activity of tefluthrin insecticide at any concentration tested.