Male-Produced Aggregation Pheromone Blend in Platypus koryoensis

The ambrosia beetle, Platypus koryoensis, is a vector of Korean oak wilt disease, which causes massive mortality of oak trees (mainly Quercus mongolica) in Korea. So that a semiochemical-based control method could be developed, its aggregation pheromone was investigated. Whole body extract and body part extracts of male and female P. koryoensis were analysized using gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). All samples of male extracts contained nerol, neral, geraniol, and geranial. Those compounds were detected from female whole body extract as minor constituents and not detected from any female body part extracts. In addition to those compounds, citronellol was detected from the extract of boring dust produced by an unmated male. However, none of the five compounds were detected from the extract of boring dust produced by mated males and females or in artificial sawdust obtained from a beetle-infected Q. mongolica log. Male and female antennae of P. koryoensis responded to all five compounds in an electroantennography test. The blend of five components was tested in the field and attractive for male and female P. koryoensis. This result suggested that the blend of citronellol, nerol, neral, geraniol, and geranial served as an aggregation pheromone to P. koryoensis.