The attractant aggregation pheromone of the northern spruce engraver, Ips perturbatus (Eichhoff), consists of ipsenol, ipsdienol, and cis-verbenol.� These pheromone components were identified by GC-FID and GC-MS from Porapak Q and abdominal tissue extracts, elicited responses in GC-EAD assays, and were attractive in the field in Lindgren funnel trap assays (Holsten et al. 2000).� In two field behavioral assays of these and other semiochemicals, over 59, 000 I. perturbatus were trapped at one site in south-central Alaska (Kenai Peninsula) and nearly 62,000 I. perturbatus were trapped at a second site in interior Alaska (near Tok).� At both sites the highest response was to the three-component attractant� (mean=203/week, Granite Creek; mean=363/week, Tok), and the response to attractant was interrupted in descending order by enantiomerically pure (+)-verbenone, conophthorin, enantiomerically pure (�)-verbenone, and commercially available [84% (�)]-verbenone. When commercially available verbenone was combined with conophthorin, the flight response of I. perturbatus was reduced by 27X (Granite Creek) and by 37X (Tok) (means=7.5/week and 9.75/week, respectively).� Dissection of genitalia revealed that during the first week of flight (May 26-30, 2001), the I. perturbatus that responded at Granite Creek were approximately 50% male, and there was no apparent treatment effect on the percentage of males responding.� Two species of Scolytidae and one species of Colydiidae also responded in large numbers to the treatments.� At Granite Creek, over 4,200 specimens of the twig beetles, Pityophthorus nitidulus Mannerheim and P. recens Bright were attracted primarily to conophthorin-baited traps. These species have been collected in this area under the bark of branches of Lutz spruce, Picea� xlutzii, infested with I. perturbatus.� At Tok, nearly 1,300 specimens of the cylindrical bark beetle, Lasconotus borealis Horn also responded primarily to treatments containing conophthorin.�