ATTRACTION OF JAPANESE-BEETLES (COLEOPTERA, SCARABAEIDAE) TO HOST-PLANT VOLATILES IN-FIELD TRAPPING EXPERIMENTS

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