Effects of Volatile Emissions of Picea abies Fresh Debris on Ips duplicatus Response to Characteristic Synthetic Pheromone

Abstract

Ips duplicatus is an important pest of Norway spruce (Picea abies) planted outside of its natural range. This species uses olfactory signals to identify the spruce trees favourable for colonisation. The knowledge of the beetles’ response to these stimuli is important for managing this pest. Therefore, the response of Ips duplicatus to a specific synthetic pheromone was investigated under some natural sources of volatile emissions characteristic of Norway spruce. The pheromone traps were installed in two types of forests: one with fresh and large Norway spruce stumps and piles of branches, releasing large amounts of host volatile substances (terpenes and alcohols) and one without such fresh material. The experiment was repeated in three pairs of sites located in plantations out of the natural range of Norway spruce. Finally it was found that Ips duplicatus beetles, regardless of sex, have been concentrated in areas where large amounts of fresh material were available, confirming that Ips duplicatus beetles are using both natural pheromones and specific host volatiles as olfactory stimuli in searching for breeding material.