Response of Dendroctonus brevicomis to different release rates of nonhost angiosperm volatiles and verbenone in trapping and tree protection studies

Abstract

A blend of eight nonhost angiosperm volatiles (benzyl alcohol, benzaldehyde, guaiacol, nonanal, salicylaldehyde, (E)‐2‐hexenal, (E)‐2‐hexen‐1‐ol and (Z)‐2‐hexen‐1‐ol) without [NAV] and with [NAVV] (–)‐verbenone (4,6,6‐trimethylbicyclo[3.1.1]hept‐3‐en‐2‐one) were tested at low (L), medium (M) and high (H) release rates for their ability to reduce attraction of western pine beetle, Dendroctonus brevicomis LeConte, to attractant‐baited (exo‐brevicomin [racemic, 3 mg/d], frontalin [racemic, 3 mg/d] and myrcene [18 mg/d]) multiple funnel traps. NAV‐L (40 mg/d) had no significant effect. Verbenone alone (50 mg/d) and NAV‐M (240 mg/d) both significantly reduced attraction, but no significant difference was observed between the two treatment means. NAV‐H (430 mg/d) significantly reduced catches by ∼60% and 78% compared to verbenone alone and the baited control, respectively. In a second experiment, combining (–)‐verbenone with NAV (NAVV) increased the effects observed in Experiment 1. NAVV‐M (240 mg/d) resulted in an ∼69% and 83% reduction in trap catch compared to verbenone alone and the baited control, respectively. Significantly fewer D. brevicomis were captured in NAVV‐H (430 mg/d) than any other treatment resulting in an ∼93% reduction in trap catch compared to the baited control. In a third experiment, NAVV was tested at three release rates for its ability to protect individual ponderosa pines, Pinus ponderosa Dougl. ex Laws., from attack by D. brevicomis. Cumulative release rates varied in direct proportion to tree diameter, but represented quarter, half and full NAVV rates. NAVV significantly reduced the density of D. brevicomis attacks, D. brevicomis successful attacks, and levels of tree mortality on attractant‐baited trees. Only three of 15 NAVV‐treated trees died from D. brevicomis attack while ∼93% mortality (14/15) was observed in the untreated, baited control. Quarter and half rates were ineffective for reducing tree mortality.

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

“…Verbenone is hypothesized to function for D. frontalis and many other bark beetle systems as both an antiaggregation pheromone that signals complete colonization of the host bole, and as a microbe-generated indicator of host decay and unsuitability (Byers, 1989;Lindgren and Miller, 2002;Sullivan, 2011). In trapping and tree protection studies, verbenone significantly enhances the capacity of nonhost volatiles to inhibit attraction and attacks by Dendroctonus Fettig et al, 2009) and Ips (Zhang, 2003;Zhang and Schlyter, 2003;Graves et al, 2008;Etxebeste and Pajares, 2011), and it may prove so for D. frontalis also.…”

“…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).…”

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.…”

“…To ensure that this did not infl uence the results of our fi eld Dendroctonus brevicomis LeConte (John et al, 1984) and the mountain pine beetle, Dendroctonus ponderosae Hopkins (Greis et al, 1990;Pureswaran et al, 2000). 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.…”

Transgenic cry1C⁎ gene rough rice line T1C-19 does not change the host preferences of the non-target stored product pest, Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae), and its parasitoid wasp, Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae)

“…Olfactory cues can mediate long-range attraction (Jyothi et al, 2002;Van Naters and Carlson, 2006;Gallego et al, 2008;Fettig et al, 2009;Hu et al, 2009;Zhuge et al, 2010). For example, the onion fly, Delia antiqua, is attracted to the host volatile dipropyl disulfide from distances of 100 m or more (Judd and Borden, 1989).…”