Protection of lodgepole pine from attack by the mountain pine beetle, Dendroctonus ponderosae (Coleoptera: Scolytidae) using high doses of verbenone in combination with nonhost bark volatiles

Abstract

We evaluated the antiaggregation pheromone verbenone at low and high doses alone and with a seven-component repellent blend of nonhost angiosperm bark volatiles (NHVs) for their ability to deter attack by the mountain pine beetle, Dendroctonus ponderosae Hopkins. Release devices containing antiaggregants were deployed at 16 points on a 10-m grid in 40 × 40-m plots near Williams Lake, B.C. in June 2001. In 10 control plots with no antiaggregants, single pheromone-baited trees, at the plot centre were all mass-attacked by the mountain pine beetle by early October, as were 26.6% of the 432 lodgepole pines within the boundaries of the plots. In contrast, in plots treated with a high dose of verbenone plus NHVs, two of the central, pheromone-baited trees escaped any attack whatsoever, four of 10 plots had no surrounding trees attacked and only 2.1% of the total of 523 surrounding trees were mass-attacked. Density of attacked and mass-attacked trees was highest within 5 m of the central baited tree in all treatments, indicating that those beetles that breached the antiaggregant grid were then drawn toward the baited tree. Operational efficacy should thus be improved in the absence of baited trees within a treated area. We conclude that high-dose verbenone plus NHV treatments could be implemented operationally as a minor component of an integrated pest management strategy for large infestations, particularly in a push-pull tactic in which beetles are pushed from one area by the antiaggregant treatment and drawn into another with attractive baits. However, the principal use would be in the short-term protection of small, high-value stands or stands of high ecological or social value.Key words: Coleoptera, Scolytidae, Dendroctonus ponderosae, chemical ecology, verbenone, pest management Nous avons évalué le phéromone antiagrégation verbenone seul à faibles et à fortes doses et avec un mélange répulsif de sept composants volatiles d'écorce d'angiosperme non-hôtes pour sa capacité à détourner les attaques du dendroctone du pin ponderosa, Dendroctonus ponderosae Hopkins. Les appareils permettant de répandre les antiagrégants ont été déployés sur 16 stations réparties selon un quadrillage de 10 m dans des parcelles de 40 × 40 m situées près de Williams Lake, C.-B., en juin 2001. Dans les 10 parcelles témoins sans antiagrégants, les arbres individuels traités comme appât aux phéromones, situés au centre des parcelles ont tous été attaqués massivement par le dendroctone dès le début d'octobre, ainsi que 26 % des 432 pins lodgepoles retrouvés dans les limites des parcelles. Par contre, dans le cas des parcelles traitées avec une forte dose de verbenone additionné du mélange répulsif, deux des arbres du centre traités comme appât aux phéromones ont échappé à toutes les attaques, quatre des 10 parcelles n'ont eu aucun arbre attaqué et seulement 2,1 % des 523 arbres situés à proximité ont été attaqués massivement. La densité des arbres attaqués et attaqués massivement était plus élevée en deçà de 5 m de l'arbre appât dans tous les...

Evaluation of the push-pull tactic against the mountain pine beetle using verbenone and non-host volatiles in combination with pheromone-baited trees

“…Therefore, using the same NHV blend in tests of either the push or the push-pull tactics might not have been necessary, although there would have been no negative impact. There was much less concentration of attack around the central baited trees than observed by Borden et al (2003). This may have been caused by 21.2% fewer available trees ≥ 17.5 cm dbh than in the previous work, and a higher beetle pressure that resulted in a 70% greater incidence of massattacked trees (based on the bait-only controls), both factors acting to distribute the attack evenly throughout the plots.…”

Aerially applied verbenone-releasing laminated flakes protect Pinus contorta stands from attack by Dendroctonus ponderosae in California and Idaho

“…Treatments using hand-applied antiattractant pouches (Borden et al, 2003(Borden et al, , 2004 or attractant-baited lures in trap-out and concentration approaches (Gray and Borden, 1989;Borden et al, 2006) are promising for small, high-value stands, but are too laborintensive to be used over large areas. In addition, many of the stands requiring protection from D. ponderosae are steep and/or remote, presenting difficulties for deployment of hand-applied tree protection treatments.…”

“…Forest managers have therefore sought methods to mitigate the effects of this pest. Several D. ponderosae management techniques have been tested, including silvicultural treatments to reduce stand density and/or basal area (Wood et al, 1985;Amman and Logan, 1998;Fettig et al, 2006a), sanitation (McMullen et al, 1986), insecticides (Haverty et al, 1998;Naumann and Rankin, 1999;Fettig et al, 2006b), and pheromone-based strategies including aggregation pheromones deployed in trap-out, trap tree, or concentration approaches (Gray and Borden, 1989;Gibson and Weber, 2004;Borden et al, 2006) and antiaggregants to interrupt colonization of hosts (Wilson et al, 1996;Huber and Borden, 2001;Borden et al, 2003Borden et al, , 2004Borden et al, , 2006Kegley et al, 2003;Gibson and Kegley, 2004;Progar, 2005;Bentz et al, 2005;Gillette et al, 2006). As suggested above, reducing stand basal area may be the single most effective treatment (Johnstone, 2002;Safranyik et al, 2004;Whitehead and Russo, 2005;Zausen et al, 2005), but forest management objectives, particularly on public lands, often require preservation of large old-growth trees for wildlife habitat (Andrews et al, 2005).…”

Protection of spruce from colonization by the bark beetle, Ips perturbatus, in Alaska

“…Some of these studies (i.e., Bentz et al, 2005;Progar, 2005) tested verbenone over multiple years, but results showed that the efficacy was not reliable over time. With the discovery of other bark beetle repellent semiochemicals such as (E)-2-and (Z)-3-hexen-1-ol (Wilson et al, 1996), 1-hexanol, benzaldehyde, benzyl alcohol, and nonanal (Borden et al, 1998), and guaiacol, hexanal, (E)-2-hexanal, salicylaldehyde, and conophthorin (Borden et al, 2003) from various non-hosts, land managers have had a larger toolkit of potential interruptants with which to manage bark beetles.…”