Abstract
BACKGROUND Agrilus bigutattus (Fabricius) is a forest pest of increasing importance in the United Kingdom. The larvae damage weakened native oaks and are thought to contribute to premature tree death. Suspected links with acute oak decline (AOD) are not yet confirmed, but AOD‐predisposed trees appear to become more susceptible to A. biguttatus attack. Thus, management may be necessary for control of this insect. To explore the possibility of monitoring beetle populations by baited traps, the host tree volatiles regulating A. biguttatus–oak interactions were studied.RESULTSBiologically active volatile organic compounds in dynamic headspace extracts of oak foliage and bark were identified initially by coupled gas chromatography–electroantennography (GC‐EAG) and GC–mass spectrometry (GC‐MS), and the structures were confirmed by GC coinjection with authentic compounds. Of two synthetic blends of these compounds comprising the active leaf volatiles, the simpler one containing three components evoked strongly positive behavioural responses in four‐arm olfactometer tests with virgin females and males, although fresh leaf material was more efficient than the blend. The other blend, comprising a five‐component mixture made up of bark volatiles, proved to be as behaviourally active for gravid females as bark tissue.CONCLUSIONSThese initial results on A. biguttatus chemical ecology reveal aspects of the role of attractive tree volatiles in the host‐finding of beetles and underpin the development of semiochemically based surveillance strategies for this forest insect. © 2015 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Highlights
The two-spotted oak buprestid, Agrilus biguttatus (Fabricius) (Coleoptera: Buprestidae), causes damage to native oak trees in Europe, and is an exotic organism of high invasive risk to the United States.[1]
In Europe, incidences of damage have become more frequent during the last two decades,[2,3] while for the United Kingdom, trees colonised by A. biguttatus show symptoms of acute oak decline (AOD), a distinctive novel form of oak decline increasingly reported on native British oak species, Quercus petraea [(Mattuschka) Leibl.] and Q. robur (L.) (Fagaceae).[4]
To test the hypothesis that (i) virgin females and males of A. biguttatus utilise foliar volatile cues to find feeding and mating sites, and that (ii) gravid females are guided by bark volatiles to oviposition sites, we studied the behavioural responses of adult beetles to oak odour in laboratory olfactometer bioassays, captured volatiles from the leaves and bark by dynamic headspace collection and subjected volatile extracts to antennal electrophysiology to locate active compounds in gas chromatography
Summary
The two-spotted oak buprestid, Agrilus biguttatus (Fabricius) (Coleoptera: Buprestidae), causes damage to native oak trees in Europe, and is an exotic organism of high invasive risk to the United States.[1]. The beetle may vector AOD necrosis bacteria, serving as a means of introducing them into trees, being essential for AOD development,[4] may merely be a secondary coloniser of trees already infected by bacteria or just a coincidental visitor.[5]. AOD often leads to tree mortality within just a few years of the appearance of the first symptoms, i.e. cracks between bark plates from which dark fluid seeps and inner bark necrosis due to bacterial activity,[4] about 5.3% of symptomatic trees having died in monitored sites over 3–4 years of assessment[5] (Brown N et al, unpublished). Suspected links with acute oak decline (AOD) are not yet confirmed, but AOD-predisposed trees appear to become more susceptible to A. biguttatus attack. To explore the possibility of monitoring beetle populations by baited traps, the host tree volatiles regulating A. biguttatus–oak interactions were studied
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
