Verbenone‐releasing flakes protect individual Pinus contorta trees from attack by Dendroctonus ponderosae and Dendroctonus valens (Coleoptera: Curculionidae, Scolytinae)

Abstract

1 In a study site in interior northern California, twenty individual lodgepole pines Pinus contorta were sprayed with a suspension of DISRUPT Micro-Flake ® Verbenone (4,6,6-trimethylbicyclo(3.1)hept-3-en-2-one) Bark Beetle AntiAggregant flakes (Hercon Environmental, Emigsville, Pennsylvania) in water, with sticker and thickener, from ground level to a height of 7 m. Twenty trees sprayed with just water, sticker and thickener served as controls. All trees were baited immediately after spraying with mountain pine beetle Dendroctonus ponderosae aggregation pheromone lures, and lures were refreshed after 4 weeks. 2 Trees treated with verbenone had significantly lower attack density by D. ponderosae than controls at 2, 4, 6 and 8 weeks after application of flakes. 3 None of the treated trees was attacked by red turpentine beetle Dendroctonus valens , whereas control trees averaged nearly two D. valens attacks per tree, 8 weeks after treatment. 4 A dry frass index, used to predict ultimate tree mortality, was significantly higher in control trees than treated trees for all four sampling intervals. This index proved to be a significant predictor of ultimate tree mortality. 5 Ten months after application, treated trees showed significantly lower mortality than control trees.

Electrophysiological and Behavioral Responses of the Bark Beetle Dendroctonus rhizophagus to Volatiles from Host Pines and Conspecifics

“…As with D. rhizophagus, in D. valens: (1) both sexes produce the oxygenated monoterpenes myrtenal, myrtenol, verbenone, and cis-and trans-verbenol during infestation of a host Shi and Sun, 2010); (2) myrtenol and trans-verbenol are the two most abundant compounds produced by host-infesting beetles (Shi and Sun, 2010); (3) the bicyclic acetals frontalin and brevicomin, which are major components of Dendroctonus aggregation pheromones, are undetectable in beetles; (4) the host monoterpene 3-carene is an effective trap bait either alone or in combination with α-and β-pinene (Hobson et al, 1993;Sun et al, 2004;Erbilgin et al, 2007); and (5) verbenone inhibits beetle response to attractive host odors (Rappaport et al, 2001;Gillette et al, 2006;Sun et al, 2006). Noteworthy differences include: (1) greater production of trans-verbenol by female than male beetles that we observed in D. rhizophagus but which was not detected in D. valens (Shi and Sun, 2010), and (2) a modest enhancement of attractiveness of a host monoterpene lure by trans-verbenol and myrtenol was observed in D. valens , but not in D. rhizophagus in the present study.…”

Gut-Associated Bacteria of Dendroctonus valens and their Involvement in Verbenone Production

“…cis-Verbenol was shown to inhibit the response of D. valens to attractant-baited traps in America when applied with racemic ipsenol and (+)-ipsdienol but did not exert any attractive or anti-attractive function in field trapping of D. valens in China [18,73]. This gut volatile could be further converted to verbenone, which serves as an attractant to D. valens at low levels in China but as a repellent at high concentration both in North America and in China [19,47,72]. These chemicals have been successfully applied in D. valens control programs with other semiochemicals [44].…”

The pheromone verbenone and its function in Dendroctonus armandi (Coleoptera: Curculionidae: Scolytinae)

“…In bark beetles, the pheromone verbenone is produced from dietary α-pinene in the fat body (Blomquist et al, 2010) and is an anti-aggregation pheromone in most Dendroctonus spp. D. armandi infestations appear to be increasing throughout the Qinling Mountains, and it is often diffi cult to use physicochemical methods and semiochemical traps to protect healthy Chinese white pines a gainst attack by D. (Gillette et al, 2006(Gillette et al, , 2012Fettig et al, 2009). Although, a GC-MS analysis of hindgut extracts from female D. armandi detected verbenone Xie & Lv, 2012), little is known about the function of verbenone as an anti-aggregation pheromone in D. armandi.…”

“…Verbenone is a component of the pheromones produced by D. brevicomis and D. frontalis (Fettig et al, 2009;Sullivan et al, 2007). Furthermore, the use of verbenone to protect Pinus contorta trees from attack by D. ponderosae and D. valens has been extensively studied (Gillette et al, 2006(Gillette et al, , 2009(Gillette et al, , 2012.…”