Effects of a Nonpheromonal Attractant on Movement and Distribution of Adult Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae)

Abstract

Responses of adult Diabrotica virgifera virgifera LeConte to a nonpheromonal attractant (4-methoxycinnamaldehyde) were monitored in commercial 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, or 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 by any of the treatments, but unbaited yellow sticky panels in plots with 64 wicks at 40 mg each captured significantly (four times) more females than those in untreated plots. Ratios of beetles captured on sticky traps baited with attractant to those on unbaited traps were not affected significantly by the amount of attractant per wick but declined from ≈8:1 in plots with four wicks to 2:1 in plots with 64 or 252 wicks. A similar trend was observed using traps constructed from medicine vials that were or were not baited with 1.0 mg of 4-methoxycinnamaldehyde. In another study, beetles were marked and released 20 m away from either of two rows of maize that had been treated with 4-methoxycinnamaldehyde at 75 mg/m; capture in unbaited sticky traps that surrounded each release site provided no evidence that beetles were attracted toward treated rows. The attractant also did not appear to influence orientation of beetles that were observed taking flight from tops of posts 3 or 20 m from the treated rows. Given the results of these and earlier studies, nonpheromonal attractants may be of limited value in semiochemical-based broadcast baits for management of D. v. virgifera in maize.