Attraction of Tomicus yunnanensis (Coleoptera: Scolytidae) to Yunnan Pine Logs with and without Periderm or Phloem: An Effective Monitoring Bait

Abstract

The Yunnan pine shoot beetle, Tomicus yunnanensis Kirkendall and Faccoli (Coleoptera: Scolytinae) is an important pest of Yunnan pine (Pinus yunnanensis Franch) in China. Experiments with host log baits were done to develop a pest monitoring system using host tree kairomone. Five Yunnan pine logs (each 10–15 cm diam. × 30-cm long) in a trap-log bundle were treated by peeling periderm (outer bark) off to expose the phloem, and half of each log was covered with sticky adhesive to capture any attracted adult beetles. Significantly, more beetles were attracted and caught on the periderm-peeled logs (ca 30 beetles/m2 log surface/day) than on untreated control logs with adhesive (ca 2.5/m2/day). No significant differences were observed between catches on logs taken from lower or upper halves of Yunnan pines. T. yunnanensis flies mostly during the afternoon according to trap catches throughout the day. Attraction to the periderm-peeled logs decreased considerably when they were peeled further to remove the phloem, indicating phloem volatiles play a role in selection of the host by the beetle. The readily-available log baits appear useful for monitoring pine shoot beetle populations in integrated pest management programs.