Synthetic herbivore-induced plant volatiles as field attractants for beneficial insects

Evidence for field attraction by beneficial insects to synthetic herbivore-induced plant volatiles (HIPVs) is presented. Three synthetic HIPVs (methyl salicylate, (Z)-3-hexenyl acetate, (E)-4,8-dimethyl-1,3,7-nonatriene) were evaluated in a Washington state hop yard during April-October 2002 for attractiveness to beneficial insects. The predatory mirid, Deraeocoris brevis (Uhler), and the anthocorid, Orius tristicolor (White), were attracted to sticky cards baited with (E) -3-hexenyl acetate, while the geocorid, Geocoris pallens Stal., and hover flies (Syrphidae) were attracted to methyl salicylate-baited cards. The coccinellid, Stethorus punctum picipes (Casey), was attracted to both HIPVs in July and September. The (E)-4,8-dimethyl-1,3,7-nonatriene did not attract any beneficial insects. Lygus hesperus Knight, Leptothrips mali (Fitch), Anagrus spp., other Miridae, Coccinellidae, and parasitic Hymenoptera were not attracted to the three HIPVs tested. The possible exploitation of HIPVs in enhancing spring populations of beneficial insects and conservation biological control in cropping systems is discussed.