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Trypodendron retusum (LeConte) (Coleoptera: Curculionidae: Scolytinae) females excised from newly attacked trembling aspen, Populus tremuloides Michaux (Salicaceae), were shown for the first time to produce the aggregation pheromone (+)-lineatin. Coupled gas chromatographic-electroantennographic detection analysis (GC-EAD) disclosed that the antennae of T. retusum , as well as the antennae of three sympatric species, native T. lineatum (Olivier) and T. rufitarsus (Kirby) and exotic T. domesticum (L.), respond to synthetic (+)-lineatin, but not the (−) enantiomer. In contrast, the antennae of T. betulae Swaine responded to SR- and RR- linalool oxide pyranoid and did not detect lineatin. GC-EAD analysis of volatiles from host and nonhost tree species revealed that conifer-produced α-pinene and angiosperm-produced conophthorin and salicylaldehyde were perceived by the antennae of all three native lineatin-perceiving species, suggesting behavioral activity. Field trapping experiments showed that salicylaldehyde synergized the response of coastal, but not interior, T. retusum to lineatin and inhibited the response of T. lineatum and T. rufitarsus. In the absence of salicylaldehyde, α-pinene appeared to inhibit the response of interior T. retusum to lineatin, while for T. lineatum and T. rufitarsus it had an apparent positive additive or synergistic effect. No behavioral response occurred to conophthorin. The results provide evidence for semiochemical-based reproductive isolation between T. retusum and T. betulae , and between these two angiosperm-infesting species and the two conifer-infesting species. They do not explain how isolation could be maintained between T. lineatum and T. rufitarsus. [ABSTRACT FROM AUTHOR]

The superiority of the host monoterpene myrcene as a synergist for trans-verbenol and exo-brevicomin, aggregation pheromone components of the mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae), suggests that the ancestral host of the mountain pine beetle is a pine rich in myrcene. A field trapping experiment in British Columbia testing reconstituted bole oleoresin of whitebark pine, Pinus albicaulis Engelmann, composed of mainly myrcene (20.7%), terpinolene (6.8%), and 3-carene (61.9%) showed it to be a better pheromone synergist than reconstituted bole oleoresin of lodgepole pine, Pinus contorta variety latifolia Engelmann, which contained only 2.7, 1.0, and 6.0%, respectively, of the above-mentioned three com- pounds. In the same experiment myrcene alone was the best synergist. In subsequent experiments, testing myrcene, terpinolene and 3-carene alone and in all possible binary and ternary combinations, a 50:50 blend of myrcene and terpinolene released at the same rate as either compound alone generally resulted in trap catches ≈3 times higher than with myrcene as a synergist. This result held as long as the terpinolene was free of contaminants, and the traps were in the open, well away from potential interference of semiochemicals emitted by newly attacked trees. 3-Carene seemed to be inert or slightly inhibitory. No single monoterpene tested alone or in binary or ternary combination in the absence of pheromones was attractive. There was no effect of doubling or tripling the release rate of myrcene or terpinolene. In five of nine experiments, adding terpinolene to myrcene caused a significant increase in the percentage of female mountain pine beetles captured. Among host pines, the presence of highly synergistic monoterpenes at various levels in combination with other monoterpenes that are apparently either inert or inhibitory could account for different degrees of pheromone synergism, and thus host preference. The highly synergistic effect of combining myrcene plus terpinolene with the mountain pine beetle aggregation pheromone components opens up the potential for suppression of populations through semiochemical-based mass trapping. [ABSTRACT FROM AUTHOR]

Damage caused by the poplar-and-willow borer, Cryptorhynchus lapathi (L.) (Co-leoptera: Curculionidae), is reported to vary among hybrid poplar clones. We evaluated oviposition preferences and larval success in four hybrid poplars on potted and field-planted trees. Oviposition occurred somewhat less frequently and abundantly on two clones with Populus maximowiczii Henry parentage in field-planted and potted trees, and 'significantly fewer larvae survived to adulthood on those clones. No adults emerged from field-planted NM 6 (Populus nigra L. × P. maximowiczii) and four emerged from TM 256-28 (Populus trichocarpa Torrey & Gray × P. maximowiczii) on which male-female pairs of C. lapathi had been caged. In contrast, 50 and 140 adults emerged over the same 2-yr period from two susceptible clones (n = 20), TD 52-226 (P. trichocarpa × Populus deltoides Bartram ex Marshall) and TN 302-9 (P. trichocarpa × P. nigra) , respectively. Thus, resistance expressed by clones with P. maximowiczii parentage partially involves decreased levels of oviposition, but more significantly, antibiosis in resistant clones prevents the development of larvae, probably in early spring. [ABSTRACT FROM AUTHOR]

We conducted four behavioral choice tests in stands of mature lodgepole pine in British Columbia, from 1988 to 1991, to determine the dose-dependent responses of Orthotomicus latidens (LeConte) and Ips pini (Say) to their respective pheromones. Dose-dependent responses were exhibited by I. pini to (±)-ipsdienol and lanierone, with trap catches directly proportional to pheromone release rates. We found differences in sex ratio of I. pini in their responses to ipsdienol but not lanierone. There was no dose-dependent response exhibited by O. latidens to its pheromone, (±)-ipsenol, with or without the presence of the host kairomone, (-)-β-phellandrene. The bark beetle predator, Enoclerus lecontei (Wolcott), showed a dose-dependent response to lanierone. Thanasimus undatulus (Say) was attracted to ipsenol in a dose-dependent fashion only when traps were also baited with β-phellandrene. Neither T undatulus nor E. sphegeus (F.) exhibited dose-dependent responses to ipsdienol. [ABSTRACT FROM AUTHOR]

Induced (traumatic) resin in white spruce (Picea glauca (Moench) Voss) leaders resistant or susceptible to the white pine weevil (Pissodes strobi Peck) was analyzed for volatile terpenes and diterpene resin acids after simulated white pine weevil damage. Leaders from 331 trees were wounded just below the apical bud with a 1-mm diameter drill, coinciding with the natural time of weevil oviposition in the spring. Leaders were removed in the fall, and the bark and xylem from the upper and lower regions of the leader extracted and analyzed by gas chromatography. [ABSTRACT FROM PUBLISHER]

Reconstructs infestations of white pine weevil in naturally regenerated spruce stands by examining standing and felled trees in the McGregor Model Forest in northern British Columbia. Subzones where infestations were common; Percentage of all stem defects in felled trees that were caused by weevil; Differences in the frequency distributions of different types of weevil-caused defect between subzones.

Protocols for pheromone-based mass-trapping of the Asian palm weevil, Rhynchophorus ferrugineus (Olivier), are presented. The aggregation pheromone, ferrugineol (4-methyl-5-nonanol) released at 3 mg per 24 h was numerically, but not statistically, superior to lower doses, and this rate is recommended for operational trapping programmes. Trap captures were maximized by placing traps at ground level or 2 m high. Vane traps were superior to bucket traps. Insecticide free traps containing funnels to prevent weevil escape were equally as effective as traps using insecticide to retain weevils. Synergism between ferrugineol and host palm volatiles was demonstrated and necessitates the inclusion of palm material in traps for maximum trapping efficacy. Both the Asian palm weevil and coconut rhinoceros beetle, Oryctes rhinoceros , were captured in the same traps without interference between their respective pheromones. These results have led in part to pheromone-based mass-trapping of the Asian palm weevil throughout the Middle East where the weevil is a serious introduced pest of date palms. [ABSTRACT FROM AUTHOR]