Identification of the sex pheromone of the tree infesting Cossid Moth Coryphodema tristis (Lepidoptera: Cossidae).

Marcelo Gustavo Lorenzo,Marc Clement Bouwer,Egmont Richard Rohwer,Bernard Slippers,Michael John Wingfield,Simon Lawson,Dawit Degefu

doi:10.1371/journal.pone.0118575

Marcelo Gustavo Lorenzo, Marc Clement Bouwer + Show 5 more

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https://doi.org/10.1371/journal.pone.0118575

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Journal: PloS one	Publication Date: Mar 31, 2015
Citations: 29	License type: CC BY 4.0

Affiliation: University of Pretoria, University of the Sunshine Coast

Abstract

The cossid moth (Coryphodema tristis) has a broad range of native tree hosts in South Africa. The moth recently moved into non-native Eucalyptus plantations in South Africa, on which it now causes significant damage. Here we investigate the chemicals involved in pheromone communication between the sexes of this moth in order to better understand its ecology, and with a view to potentially develop management tools for it. In particular, we characterize female gland extracts and headspace samples through coupled gas chromatography electro-antennographic detection (GC-EAD) and two dimensional gas chromatography mass spectrometry (GCxGC-MS). Tentative identities of the potential pheromone compounds were confirmed by comparing both retention time and mass spectra with authentic standards. Two electrophysiologically active pheromone compounds, tetradecyl acetate (14:OAc) and Z9-tetradecenyl acetate (Z9-14:OAc) were identified from pheromone gland extracts, and an additional compound (Z9-14:OH) from headspace samples. We further determined dose response curves for the identified compounds and six other structurally similar compounds that are common to the order Cossidae. Male antennae showed superior sensitivity toward Z9-14:OAc, Z7-tetradecenyl acetate (Z7-14:OAc), E9-tetradecenyl acetate (E9-14:OAc), Z9-tetradecenol (Z9-14:OH) and Z9-tetradecenal (Z9-14:Ald) when compared to female antennae. While we could show electrophysiological responses to single pheromone compounds, behavioral attraction of males was dependent on the synergistic effect of at least two of these compounds. Signal specificity is shown to be gained through pheromone blends. A field trial showed that a significant number of males were caught only in traps baited with a combination of Z9-14:OAc (circa 95% of the ratio) and Z9-14:OH. Addition of 14:OAc to this mixture also improved the number of males caught, although not significantly. This study represents a major step towards developing a useful attractant to be used in management tools for C. tristis and contributes to the understanding of chemical communication and biology of this group of insects.

Highlights

The quince borer Coryphodema tristis, Drury, 1782 (Lepidoptera: Cossidae) is native to South Africa
The smaller response occurred at 6.38 minutes (RI = 1799.0) and coincided with the elution time of Z9-14:OAc on the gas chromatography electro-antennographic detection (GC-EAD) system
Analysis of pheromone gland extracts from the cossid moth, C. tristis in this study revealed that Z9-14:OAc and 14:OAc were possible pheromone candidates

Summary

Introduction

The quince borer Coryphodema tristis, Drury, 1782 (Lepidoptera: Cossidae) is native to South Africa. The larvae of this moth has long been known to be a pest of grape vine, apple, quince and sugar pear trees, especially in the Cape Town region [1, 2]. Population levels and the extent of the damage can be confirmed only by felling infested trees, which is obviously not ideal for large-scale assessments. Adult moths are active for a short period in early spring. This narrow period of emergence provides an opportunity to monitor the extent of the infestation indirectly, if a trapping tool were available for the adults

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