Tobias Heber

Different trap types and attractant compositions were tested with the goal of attracting as many individuals of Hylobius abietis as possible while assuring a minimal bycatch of nontarget species with regard to the family Carabidae on three study sites in the east of Germany. The results revealed a modified pitfall trap based on a model by Nordlander (1987, Scandinavian Journal of Forest Research , 2, 199–213.) as the most effective trap type with a high degree of selectivity and minimal ecological side effects. The modified Nordlander trap is suitable for potential H. abietis mass trapping as an instrument of integrated pest management. Two field trials testing different attractant compositions showed that a simple attractant combination of (−)‐α‐pinene and ethanol is as effective as other more complex combinations and thus preferable for mass trapping efforts. The addition of the monoterpenes camphene, Δ‐3‐carene, ocimene and terpinolene to the combination of (−)‐α‐pinene and ethanol did not increase trapping numbers significantly. Trapping numbers of H. abietis indicate that a reduction of the local H. abietis population by trapping is possible, though further research about the influence of mass trapping on regeneration damage is recommended.

This study focused on elucidating the possibilities of improving current trapping methods for Ips typographus (Linnaeus, 1758). Three field experiments were conducted simultaneously in one study area in the German federal state of Saxony. A comparison of six different commercial attractants revealed a significant superiority of Typosan^®, especially for adult beetles after hibernation in the phase of their first swarming. It also attracted fewer individuals of Thanasimus spp. than the other highly attractive products Pheroprax^® and IT Ecolure Extra^®. Increasing the Pheroprax^® application rate by using four instead of one dispenser in a single trap increased the total catch of I. typographus only by 15.5%. In contrast, Thanasimus spp. catch increased by 195.5% when four dispensers were used. A test of different trap types showed a species-specific catching capability, with the 12-funnel WitaTrap^® being the most effective in catching I. typographus. The quantity of Thanasimus spp. bycatch in multiple-funnel traps demonstrated the necessity of a selective mechanism to minimize impacts on predator populations. Although we were not able to identify new milestones towards mass trapping, this study contributes to necessary improvements of current trapping methods. Especially in future stands with a smaller share of Norway spruce (Picea abies Karsten, 1881) the weakened beetle population in spring could be effectively reduced by properly conducted mass trapping.