Response of the pine engraver, Ips pini (Say) (Coleoptera: Scolytidae), to conophthorin and other angiosperm bark volatiles in the avoidance of non‐hosts

Abstract

1 Seventeen non-host angiosperm bark volatiles, seven of which are antennally active to Ips pini (Say), the pine engraver (PE), were tested for their ability to disrupt the response of the PE to pheromone-baited traps. 2 Four green leaf volatiles (GLVs) were tested [1-hexanol (Z)-3-hexen-1-ol, hexanal, and (E)-2-hexenal]. None had any disruptive effect singly, as a group or in all possible blends based on functional groups, despite the fact that the two aldehydes were antennally active. These compounds may have, in some instances, actually masked the disruptive effect of other compounds. The PE thus differs in its response from other Scolytidae, including other Ips spp. 3 Eight non-host volatiles that were antennally active to other bark beetles, but not to PEs, had no disruptive effect, validating the use of coupled gas chromatographic-electroantennographic detection analyses to detect compounds with potential behavioural activity. 4 The bicyclic spiroacetal conophthorin, (E)-7-methyl-1,6-dioxaspiro[4.5]decane, was disruptive when tested alone. When blends of two aldehydes [salicylaldehyde and nonanal] plus an alcohol and a phenol [benzyl alcohol and guaiacol] were combined with conophthorin, an enhanced disruptive effect was revealed. No single compound, other than conophthorin, disrupted the pheromone-positive response and no blend that did not contain conophthorin was consistently disruptive to both sexes. Conophthorin seems to be a critical component in the non-host angiosperm message for I. pini during its host selection phase. 5 Combination of the repellent synomones, verbenone and ipsenol, with the ®ve disruptive non-host volatiles may provide a potent treatment to protect trees, logs or stands from attack by the PE.

Behavioral and electrophysiological responses of Hylastinus obscurus to volatiles released from the roots of Trifolium pratense L.

“…This compound was behaviorally inactive Behavioral and electrophysiological responses of Hylastinus obscurus to volatiles released for males, but all of the tested doses repelled females as effectively as R-limonene and S-limonene. Shown to be a green-leaves volatile by Thiéry and MarionPoll (1998), the inclusion of hexanal did not significantly reduce the attractiveness of traps baited with pheromones from Conophthorus resinosae (de Groot and MacDonald, 1999) and Ips pini (Huber et al, 2001). In fact, Jaffé et al (1993) showed that hexanal synergized a mix of different pineapple and coconut volatiles, which attracted palm weevils, Rhynchophorus palmarum, in laboratory assays, but not in field tests.…”

Interruption of aggregation pheromone in Ips typographus (L.) (Col. Scolytidae) by non‐host bark volatiles

“…For example, in GC-EAD analyses of Betula pendula Roth, B. pubescens Ehrh and Populus tremula L. leaf and bark volatiles, the antennae of I. typographus strongly responded to C 6 -alcohols (GLVs): 1-hexanol and (Z)-3-hexen-1-ol from both leaves and bark, and (E)-2-hexen-1-ol from the nonhost intact leaves (Zhang et al, 1999a and to trans-conophthorin (tC) and C 8 -alcohols: 3-octanol and 1-octen-3-ol from the nonhost bark . NHVs from natural materials (Schroeder, 1992;Byers et al, 1998Byers et al, , 2000 or from dispensers with individual or blends of synthetic chemicals disrupt the responses of over 20 species of conifer bark beetles to their aggregation pheromones or host kairomones (Dickens et al, 1991(Dickens et al, , 1992aWilson et al, 1996;Guerrero et al, 1997;Huber et al, 1999, Zhang et al, 1999bPoland & Haack, 2000;Schlyter et al, 2000;Huber et al, 2000bHuber et al, , 2001Huber & Borden, 2001a,b;.…”

Antennal responses of the western pine beetle, Dendroctonus brevicomis (Coleoptera: Curculionidae), to stem volatiles of its primary host, Pinus ponderosa, and nine sympatric nonhost angiosperms and conifers

“…There is some existing evidence that bark and ambrosia beetles display positive, or at least not negative chemotaxis, to mixtures of nonhost volatiles and pheromone components (Deglow & Borden 1998a,b;Huber et al 2001). Huber et al (2001) hypothesized that bark beetles foraging for host material that was shrouded in leafy plants may often encounter mixtures of green leaf volatiles (GLVs) and conspecific aggregation pheromone components.…”

“…Huber et al (2001) hypothesized that bark beetles foraging for host material that was shrouded in leafy plants may often encounter mixtures of green leaf volatiles (GLVs) and conspecific aggregation pheromone components. Since it would be beneficial for the foraging beetle to orient towards the shrouded host, it may display positive chemotaxis or may Vol.…”