Field response of the dutch elm disease vectors,Scolytus multistriatus (Marsham) andS. scolytus (F.) (Coleoptera: Scolytidae) to 4-methyl-3-heptanol baits containing α-, ß-,δ-, or δ-multistriatin.

The field responses of English populations of the Dutch elm disease vectors,Scolytus multistriatus andS. scolytus to baits containing 4-methyl-3-heptanol, a host synergist [(-)-α-cubebene or (-)-limonene] and (±)-α-, (+)-ß-, (-)-ß-, (±)-γ-, or (±)-δ-multistriatin were examined. (±)-α-Multistriatin, released at 5-10 µg/day, enhanced the response ofS. multistriatus to baits containing 4-methyl-3-heptanol and either of the host synergists but had no effect on the capture ofS. scolytus. The release of larger amounts (57 or 365 µg/day) of (±)-α-multistriatin interrupted the response of both species to the 4-methyl-3-heptanol baits. It appears that α-multistriatin has multiple functions as a behavior-modifying substance for the two beetles. The (+)-ß-, (-)-ß-, (±)-γ-, and (±)-δ-multistriatins were inactive when released at 5-10 µg/day. The results of these field experiments suggest that one bait can be formulated to capture both species.