Nationwide survey for invasive wood-boring and bark beetles (Coleoptera) using traps baited with pheromones and kairomones

Abstract

Exotic wood borers and bark beetles (WBBB) pose a considerable threat to trees and forests, and the challenge of timely detection and response is significant. The Ministry of Agriculture and Forestry implemented a national surveillance programme for invasive WBBB targeted at species that could become serious pests of New Zealand's large conifer plantations and unique native forests. The three aims for 2002–2005 were for the programme to act as an early-warning system to detect newly established beetles, to test the efficacy of different lures for established or newly established exotic species and to study the effects of trap placement and proximity of host trees on trap catch in order to improve trap efficiency. For the general surveillance programme, up to 580 funnel traps baited with either α-pinene and ethanol, β-pinene and ethanol, frontalin and ethanol or ipsdienol were placed around New Zealand at high-risk sites including all major seaports, international airports, devanning sites and also in forests near high-risk sites. Additional traps were used to compare these lures with unbaited control traps to assess their effectiveness in catching established exotic WBBB, and to assess the effects of placing traps at varying distances from host trees. Over 27,000 beetles were caught during the general survey from 2002 to 2004, and no new establishments were detected. Between 51% and 88% of all catches were of Scolytinae or Cerambycidae, and most of these were accounted for by the three exotic species Arhopalus ferus, Hylurgus ligniperda and Hylastes ater. Overall, these three species were most attracted to traps baited with α-pinene and ethanol. Catches ‘near’ and ‘far’ from trees differed little for A. ferus and H. ater. H. ligniperda were caught in significantly lower numbers near trees. The results confirm that a trapping programme like the one described here is likely to assist with the early detection of any new establishments, which would improve the chances of successful eradication.