Synthetic attractants for the bark beetle parasitoid Coeloides bostrichorum Giraud (Hymenoptera : Braconidae)

Coeloides bostrichorum Giraud parasitoids (Hymenoptera: Braconidae) attack late larval stages of various bark beetle species breeding in spruce. Volat ile compounds collected from Norway spruce (Picea abies) infested by Ips ty pographus L. (Coleoptera: Scolytidae) were analysed by coupled gas chromato graphy-mass spectrometry (GC-MS) and GC-electroantennographic detection (GC -EAD). Monoterpene hydrocarbons an the predominant volatile compounds of fr esh Norway spruce, while the presence of oxygenated monoterpenes indicates damaged trees. Between one and eight EAD-active oxygenated monoterpenes wer e used, in amounts reflecting their natural abundance in spruce trees conta ining bark beetle larvae, to prepare fia e synthetic baits which were teste d in wind runner bioassays. Odour samples collected from spruce logs contai ning the preferred host stage were attractive, while similar samples from u ninfested logs failed to elicit any flight activity. However, when a four- or an eight-component synthetic bait was added to volatiles collected from uninfested spruce logs, this combination was as attractive as volatiles col lected from infested spruce logs.