Responses of Dendroctonus brevicomis (Coleoptera: Curculionidae) in Behavioral Assays: Implications to Development of a Semiochemical-Based Tool for Tree Protection

Abstract

Currently, techniques for managing western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae, Scolytinae), infestations are limited to tree removals (thinning) that reduce stand density and presumably host susceptibility, and/or the use of insecticides to protect individual trees. There continues to be significant interest in developing an effective semiochemical-based tool for protecting trees from D. brevicomis attack, largely as an alternative to conventional insecticides. The responses of D. brevicomis to tree volatiles and verbenone were documented in eight experiments (trapping assays) conducted over a 4-yr period in which 88,942 individuals were collected. Geraniol, a tree volatile unique to Pinus ponderosa that elicits female-specific antennal responses in D. brevicomis, did not affect D. brevicomis behavior. Blends of two green leaf alcohols [hexanol + (Z)-3-hexen-1-ol] tested at two release rates (5.0 and 100.0 mg/d) had no effect on the response of D. brevicomis to attractant-baited traps. A nine-component blend [benzaldehyde, benzyl alcohol, guaiacol, nonanal, salicylaldehyde, (E)-2-hexenal, (E)-2-hexen-1-ol, (Z)-2-hexen-1-ol, and (-) -verbenone; NAVV] and subsequent revisions of this blend disrupted the response of D. brevicomis to attractant-baited traps in all experiments. The inhibitory effect of a revised five-component blend [nonanal, (E)-2-hexenal, (E)-2-hexen-1-ol, (Z)-2-hexen-1-ol, and (-)-verbenone; NAVV5] on the response of mountain pine beetle, D. ponderosae Hopkins, to attractant-baited traps was also documented. Acetophenone significantly reduced D. brevicomis attraction, but was not as effective as verbenone alone. Acetophenone increased the effectiveness of NAVV5 in one of two experiments. Furthermore, by adding acetophenone to NAVV5 we were able to remove the aldehydes from NAVV5 without compromising effectiveness, resulting in a novel four-component blend [acetophenone, (E)-2-hexen-1-ol + (Z)-2-hexen-1-ol, and (-)-verbenone; Verbenone Plus]. We discuss the implications of these and other results to development of Verbenone Plus as a semiochemical-based tool for management of D. brevicomis and D. ponderosae infestations.

Southern Pine Beetle, Dendroctonus frontalis, Antennal and Behavioral Responses to Nonhost Leaf and Bark Volatiles

“…There is an accumulating body of evidence suggesting that foraging coniferophagous bark beetles detect and avoid volatile compounds released from the leaves and/or bark of angiosperms and other nonhost taxa ('nonhost volatiles'), and thereby may improve foraging efficiency by avoiding nonhostdominated habitats and landings on unsuitable trees. Numerous individual nonhost volatiles have been identified and shown to inhibit coniferophagous bark beetle responses to traps baited with attractant pheromones and/or host kairomones (e.g., Dickens et al, 1992;Huber and Borden, 2003;summarized in Zhang and Schlyter, 2004;Zhang et al, 2007;Dodds and Miller, 2010;Fettig et al, 2012). Furthermore, nonhost volatiles have been used with some success to protect individual trees from bark beetle attacks Jakuš et al, 2003;Fettig et al, 2009;Schiebe et al, 2011;Schlyter, 2012).…”

Field response of Hylastinus obscurus Marsham (Coleoptera: Curculionidae) to E-2-hexenal and limonene, two host-derived semiochemicals

“…Under IPM, semiochemicals are used to monitor pest populations as well as for mass trapping and mating disruption (Campion et al, 1985). Examples of semiochemicals for pest control have been reported by various authors, including the development of semiochemical-based tools to protect trees from bark beetle infestations using mainly antiaggregation and aggregation pheromones (Fettig et al, 2012). Gillette et al (2009) indicated that the objective is to attract, retain and later destroy the pest.…”

Efficacy of “Verbenone Plus” for Protecting Ponderosa Pine Trees and Stands From <I>Dendroctonus brevicomis</I> (Coleoptera: Curculionidae) Attack in British Columbia and California

“…The effect was conÞrmed in several additional studies (Fettig et al 2009b). Fettig et al (2012) reported a revised Þve-component blend [nonanal, (E)-2-hexenal, (E)-2-hexen-1-ol, (Z)-2-hexen-1-ol, and (Ð)-verbenone; RB] signiÞcantly reduced D. brevicomis attraction by 73.1% compared with attractant-baited traps (Fettig et al 2012). In experiment 1, RB ϩ WPB had no effect on the density of D. brevicomis attacks on attractant-baited trees (Fig.…”

“…However, initial blends were complex and likely not feasible for operational use. Fettig et al (2012) further examined the response of D. brevicomis to several blends of nonhost angiosperm volatiles and (Ð)-verbenone in attractantbaited traps in hopes of improving the efÞcacy of their nine-component blend and reducing the number of components involved. They documented the inhibitory effect of a revised Þve-component blend [nonanal, (E)-2-hexenal, (E)-2-hexen-1-ol, (Z)-2-hexen-1-ol, and (Ð)-verbenone], and later demonstrated that adding acetophenone (Erbilgin et al 2007(Erbilgin et al , 2008 to this blend allowed removal of the aldehydes [nonanal and (E)-2-hexenal] without compromising efÞcacy.…”

“…They documented the inhibitory effect of a revised Þve-component blend [nonanal, (E)-2-hexenal, (E)-2-hexen-1-ol, (Z)-2-hexen-1-ol, and (Ð)-verbenone], and later demonstrated that adding acetophenone (Erbilgin et al 2007(Erbilgin et al , 2008 to this blend allowed removal of the aldehydes [nonanal and (E)-2-hexenal] without compromising efÞcacy. The resulting four-component blend [acetophenone, (E)-2-hexen-1-ol ϩ (Z)-2-hexen-1-ol, and (Ð)-verbenone], termed Verbenone Plus, has been demonstrated to inhibit the response of D. brevicomis to attractant-baited traps in several studies (Fettig et al 2012). The primary objective of our research was to determine the effectiveness of Verbenone Plus for protecting individual trees and forest stands from mortality attributed to D. brevicomis attack in British Columbia and California.…”