Estimating the most effective and economical pheromone for monitoring the European spruce bark beetle

In recent decades, there have been an increasing number of outbreaks of Ips typographus in Europe. A large amount of sanitary felling has taken place, with significant economic and ecological consequences. In order to anticipate such large-scale outbreaks, an effective monitoring system should be set up. One important aspect of monitoring is deciding which pheromone to use. Therefore, we decided to test five different commercially available pheromone lures under different disturbance conditions: Pheroprax (R), IT Ecolure Extra (R), Ipstyp (R), Ipsowit (R) and Typosan (R). We investigated the ability of the pheromones to distinguish between disturbed and undisturbed locations, their cost-efficiency ratio, and side effects such as bycatch abundance and composition. We set 50 traps in two areas with sites that were disturbed and undisturbed by windstorms. We collected the catch from traps every 1-2 weeks from the end of March until the end of September in 2019. We found that IT Ecolure Extra (R), Ipsowit (R) and (R) Pheroprax (R) caught the most I. typographus and best showed changes in the trap catch of I. typographus throughout the whole season. There was a low amount of bycatch (<6% of the total catch) and a low number of predators (a few specimens), but some groups seem to prefer certain pheromones. The cost of the pheromones increased with their effectiveness. However, pheromone costs are low relative to the personnel costs involved in setting traps and collecting the catch. Based on all of the gathered data, we created an index which helps to assess the cost-efficiency of the five chosen commercially available pheromones. We also present guidelines on how to make such an index to assist other researchers in choosing the right pheromone for monitoring populations of I. typographus or other bark beetle species.

Automated summary

The study tested five commercially available pheromone lures for monitoring Ips typographus outbreaks in Europe, with IT Ecolure Extra (R), Ipsowit (R), and Pheroprax (R) showing the best effectiveness. The cost of pheromones is relatively low compared to personnel costs. An index was created to assess the cost-efficiency of the pheromones, providing guidelines for future research in selecting the right pheromone for monitoring bark beetle populations.