Five principal semiochemicals were field tested in multiple funnel traps for behavioral activity against Dendroctonusponderosae infesting lodgepole pine, Pinuscontorta var. latifolia Engelmann, in British Columbia. The basic experimental design was to test each compound by adding it in varying concentration or enantiomeric composition to a blend of other semiochemicals. (−)-trans-Verbenol was attractive to both sexes. (±)-exo-Brevicomin and (±)-frontalin (in one of two experiments) were attractive with other semiochemicals to females at a release rate of 0.05 mg/24 h. At higher release rates (±)-exo-brevicomin was inhibitory to males, and frontalin was inhibitory to both sexes. Thus both serve as multifunctional pheromones. For neither exo-brevicomin nor frontalin were the separate enantiomers attractive at the low release rate, suggesting that they had an additive effect. However, at the high release rate both enantiomers mimicked the inhibitory effect of the racemates. Verbenone acted as an antiaggregation pheromone for both sexes. Increasing the release rate of myrcene from 18 to 150 mg/24 h to approximate the release rate from a newly attacked tree had the effect of doubling the catch of responding beetles. A conceptual model is proposed for the sequential interaction of these semiochemicals in the mass attack of a tree. Pioneer females release trans-verbenol, which acts in combination with myrcene from the host tree to attract mainly males. The responding males release exo-brevicomin and later frontalin, which in combination with trans-verbenol and myrcene attract mainly females. Meanwhile autoxidation of α-pinene in the host resin results first in the production of predominately trans-verbenol, which supplements that produced by the beetles. Later, autoxidation of α-pinene and microbial conversion of cis- and trans-verbenol result in the production of the antiaggregation pheromone verbenone. This compound, in combination with large amounts of exo-brevicomin and frontalin as the tree becomes fully occupied, results in the close-range redirection of responding beetles toward nearby trees.

The pine engraver (PE), Ipspini (Say), often coexists with the mountain pine beetle (MPB), Dendroctonusponderosae Hopk., in lodgepole pine, Pinuscontorta var. latifolia Engelm. The PE colonizes the upper bole, while the MPB infests the lower bole. We investigated the hypothesis that interspecific interactions between the PE and the MPB within trees can adversely affect MPB progeny production or survival. In lodgepole pine bark attacked by both species, PE and MPB emergence holes had a strong negative interrelationship, suggesting that high numbers of one species resulted in lower numbers of the other. In the laboratory, attacks by PEs on lodgepole pine logs resulted in significantly decreased numbers of MPB progeny, particularly when MPBs and PEs were allowed to attack logs simultaneously. Reductions in MPB progeny were 92.8 and 96.2% when the ratios of attacking beetles were 100 PE: 50 MPB per square metre and 200 PE: 50 MPB per square metre, respectively, compared with that in control logs with 50 MPB per square metre. In an August field experiment, pheromone-induced attack by the PE on trees just attacked by the MPB resulted in a 72.5% reduction in mean MPB progeny production compared with that in MPB-attacked control trees. Possible reasons for the reduced success of MPB when it and the PE coinhabit the same host may be exploitation competition, interference competition, or introduction of fungal competitors deleterious to the MPB. Induced infestation by PEs of MPB-infested trees may have the potential to reduce or control MPB populations.

In laboratory and field bioassays, Gnathotrichus sulcatus responded to sulcatol (6-methyl-5-hepten-2-ol) only when both enantiomers were present. Response was greater to racemic sulcatol than to a mixture (65 : 35) of S-(+) and R-(-) enantiomers, the naturally occurring isomeric ratio. Enantiomer-specific active sites on receptor proteins in the same or different cells are implicated.

The following compounds were field tested in multiple funnel or drainpipe traps as attractants for the mountain pine beetle, Dendroctonusponderosae Hopkins, in British Columbia lodgepole pine, Pinuscontorta var. latifolia Engelm. forests: trans-verbenol, 3-caren-10-ol, acetophenone, E-2-methyl-6-methylene-octa-2,7-dienol (myrcenol) and 2-p-menthen-7-ol (all female-produced volatiles which had proven attractive in laboratory bioassays); exo-brevicomin (produced by males); and α-pinene, β-pinene, 3-carene, β-phellandrene, terpinolene and myrcene (host tree monoterpenes). trans-Verbenol was demonstrated to be a highly active aggregation pheromone, as was (±)-exo-brevicomin. Myrcene was the most effective synergistic monoterpene, while α-pinene was completely ineffective. In one experiment, 3-caren-10-ol caused a shift in favor of responding males, but the other female-produced volatiles were inactive.

f a r o l , J.H. or den^, R.G. ~r a s e r~, and A. yanchuk4Research programs to date in British Columbia on the bioloLes programmes de recherche B ce jour en Colombie-Britannique gy, damage and control of the white pine weevil, Pissodes strobi portant sur la biologie, les domrnages et le contr6le du chapeck), a pest of spruce, Picea spp. and pine, P i w spp., are reviewed.lanpn du pin blanc, Pissodes strobi (Peck), un ravageur des -ttes, Significant progress has been made in the areas of genetic resisPicea spp. et des pins, Pinus spp., ont fait l'objet d'une etude. Des tance, silvicultural and chemical control. An integrated pest progrks significatifs ont kt6 enregistres au niveau de la resistance management (IPM) system is formulated which combines silvigenetique et du conMle sylvicole et chimique. Un syseme de gesculture-driven and resistance-driven tactics. The system relies on tion integr6e des ravageurs (GIR) est formule et combine des tacaccurate hazard rating of plantation sites and requires continuous tiques dkcoulant de la sylviculture et de la resistance des arbres. monitoring of attack levels and the forecasting of plantation Le systkme repose sur une evaluation precise du risque relatif aux productivity under various IPM tactics through the use of a sites de plantation et necessite une surveillance continue des decision support system. Research needs which would increase niveaux d'attaque et de la productivite des plantations en fonceffectiveness of the IPM system are reviewed and organized in tion de diverses tactiques de GIR grlce B l'utilisation d'un systhe context of the plantation productivity cycle. tkme de prise de dkcision. Les domaines de recherche qui pourraient accroitre l'efficacitk d'un systkme GIR sont revisks et