EFFECTS OF A NONPHEROMONAL ATTRACTANT ON MOVEMENT AND DISTRIBUTION OFADULT DIABROTICA-VIRGIFERA-VIRGIFERA (COLEOPTERA, CHRYSOMELIDAE)

Responses of adult Diabrotica virgifera virgifera LeConte to a nonpher omonal attractant (4-methoxycinnamaldehyde) were monitored in commerci al fields of maize, Zea mays L. Plots (16 by 16 m) were treated with 4 , 16, or 64 cotton dental rolls (wicks) that each contained 2.5, 10, o r 40 mg of attractant or with 252 wicks at 2.5 mg each. Counts of D. v . virgifera on maize plants in plots were not significantly affected b y any of the treatments, but unbaited yellow sticky panels in plots wi th 64 wicks at 40 mg each captured significantly (four times) more fem ales than those in untreated plots. Ratios of beetles captured on stic ky traps baited with attractant to those on unbaited traps were not af fected significantly by the amount of attractant per wick but declined from almost-equal-to 8:1 in plots with four wicks to 2:1 in plots wit h 64 or 252 wicks. A similar trend was observed using traps constructe d from medicine vials that were or were not baited with 1.0 mg of 4-me thoxycinnamaldehyde. In another study, beetles were marked and release d 20 m away from either of two rows of maize that had been treated wit h 4-methoxycinnamaldehyde at 75 mg/m; capture in unbaited sticky traps that surrounded each release site provided no evidence that beetles w ere attracted toward treated rows. The attractant also did not appear to influence orientation of beetles that were observed taking flight f rom tops of posts 3 or 20 m from the treated rows. Given the results o f these and earlier studies, nonpheromonal attractants may be of limit ed value in semiochemical-based broadcast baits for management of D. v . virgifera in maize.