‘Allochthonous Kairomones’ in stands of European beech (Fagus sylvatica) – Approach for nature-based bark beetle management with clerid beetles (Thanasimus spp.)

A method of using ‘Allochthonous Kairomones’ for nature-based bark beetle management is presented. The ‘Allochthonous Kairomone’ has the function of simulating the presence of prey in order to aggregate predators to endangered places but should avoid aggregating autochthonous bark beetles. Different attractants (Sexowit® and Pheroprax®) and single components of the latter (2-methyl-3-buten-2-ol, (S)-ipsdienol and (S)-cis-verbenol) were tested in stands of European beech (Fagus sylvatica L.) near Tharandt. The most frequently aggregated predators were from the family Cleridae, Rhizophagidae and Trogossitidae. Attracted predators of the Cleridae were Thanasimus formicarius L. and Thanasimus femoralis Zett. The attractant Sexowit® seems to achieve all the requirements of an ‘Allochthonous Kairomone’ when used in stands of European beech. In comparison to the other variants, the highest number of predators was aggregated; these were mostly T. formicarius, Rhizophagus depressus F. and Rhizophagus dispar Payk. On the other hand, the lowest number of bark beetles was aggregated. Also, Pheroprax® and (S)-cis-verbenol had an aggregating effect on predators. In contrast to Sexowit®, T. femoralis and Nemosoma elongatum L. were the most abundant predators aggregated by Pheroprax®. In addition, a seasonal difference in flying activity between the predators was noted. Predators reacting to Sexowit® were more active early in the year; predators attracted by Pheroprax® were more abundant at the end of summer. The seasonal activity of predator and prey is discussed and the applicability of the used kairomones is specified. Furthermore, suggestions for additional research in application of ‘Allochthonous Kairomones’ are given.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We present a method for natural bark beetle management with ‘Allochthonous Kairomones’. ► The kairomon should simulate presence of pray but avoid aggregating autochthonous bark beetles. ► This is reached by kairomone replacement between different habitats. ► The lures Sexowit® and Pheroprax® as the (S)-cis-vebenol dispenser showed the best results. ► Most aggregated predators were Thanasimus spp., Nemosoma elongatum and Rhizophagidae.