Screening of Essential Oil Antifeedants in the Elm Pest Ambrostoma quadriimpressum (Coleoptera: Chrysomelidae)

Abstract

The leaf beetle Ambrostoma quadriimpressum Motschulsky (Coleoptera: Chrysomelidae) is a major pest of elm (Ulmus; Rosales: Ulmaceae) in eastern Asia, and there is currently no effective, environmentally friendly, chemical method for its control. In this study, we measured A. quadriimpressum adults' electrophysiological and behavioral responses to 13 compounds, including 6 plant volatiles (linalool, α-pinene, methyl salicylate, indole, di-n-octyl phthalate, dimethyl naphthalene), 4 semiochemicals (benzyl alcohol, cinnamaldehyde, 1-undecene, anethol) known to elicit responses in closely related species, 2 pungent odorants (methanol, phenol), and 1 analogue (ethyl salicylate) of an elm volatile. Female leaf beetles were highly responsive to phenol and methanol, whereas male beetles responded to di-n-octyl phthalate and dimethyl naphthalene at a concentration of 10 μg/μL. Cinnamaldehyde elicited the highest electroantennogram responses in both male and female beetles. In screenings of semiochemicals, beetles of both sexes were significantly repelled by cinnamaldehyde at 1 μg/μL. In Y-tube olfactometer tests, beetles of both sexes were significantly repelled by cinnamaldehyde, at 1 μg/μL for females and 10 μg/μL for males. In choice tests, 90% of starved beetles chose control leaves over leaves treated with cinnamaldehyde at 10 μg/μL. These results suggest that cinnamaldehyde has potential value for control of this elm pest, acting as an antifeedant compound.