Attraction of Japanese beetles (Coleoptera: Scarabaeidae) to host plant volatiles in field trapping experiments

Attraction of Japanese beetles, Popillia japonica Newman, to 17 compounds typical of those released by undamaged and insect-damaged angiosperm leaves was compared in replicated field trials. Eight compounds attracted significantly more beetles than did an unbaited trap; however, the 2 most attractive single compounds, phenylacetonitrile and (Z)-jasmone, were only approximate to 10% as effective as geraniol, a component of commercial lures. Progressive pairwise addition of less attractive volatiles to a blend of phenylacetonitrile and (Z)-jasmone resulted in increasing beetle capture. The relative attractiveness of blends of conifer/eucalyptus, fruit-like, and floral odors, plus a complete mixture of these, also was tested. Although the floral, fruit-like, and complete mixtures captured more beetles than did the conifer/eucalyptus blend or phenylacetonitrile alone, our results suggest that this polyphagous insect is likely to be attracted to many naturally occurring plant volatiles, and that as the number of components in a volatile blend increases, so Rill its attractiveness. The complete mixture of volatile compounds also attracted more green June beetles, Cotinis nitida (L)., than did the fruit-like, floral, or conifer/eucalyptus blends.