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

Abstract

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®, IT Ecolure Extra®, Ipstyp®, Ipsowit® and Typosan®. 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®, Ipsowit® and ® Pheroprax® 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.

Evaluation of Attractant Composition, Application Rate, and Trap Type for Potential Mass Trapping of Ips typographus (L.)

“…Similar results regarding the trapping of I. typographus with Typosan ® can be found with the evidence of its higher attractivity compared to Pheroprax ® [72] and its relatively low number of bycatch [71]. However, Pheroprax ® is considered to be an effective attractant for I. typographus when compared with different products in other studies [44,71,109]. IT Ecolure Mega ® was previously described as comparatively less attractive for I. typographus [110] according to the results of our study.…”

“…It is also part of the standardized bark beetle monitoring applied in the study area [26]. The attractants IT Ecolure classic ® , IT Ecolure Extra ® , and IT Ecolure Mega ® are also known from literature [44,66,67] as well as Ipsowit ® [68][69][70][71] and Typosan ® [70][71][72]. Table 1 summarizes the duration of attractivity, release rate and composition of the tested products.…”

“…Table 1 summarizes the duration of attractivity, release rate and composition of the tested products. The release rate has been determined by weekly weighing the products with a precision balance (Kern EW 150-3M), while the composition of the attractants was obtained from literature [71], where only information for IT Ecolure Extra ® was available. Since it had the same manufacturer as IT Ecolure classic ® and IT Ecolure Mega ® , information was transferred.…”

“…Since it had the same manufacturer as IT Ecolure classic ® and IT Ecolure Mega ® , information was transferred. However, it seems that only the pheromonal Forests 2021, 12, 1727 4 of 20 components were specified [71]. Cis-Verbenol was mentioned as the only constituent for the Ecolure products, but since it is crystalline and solid in pure state [73], it needs a solvent, which was not listed.…”

“…All products tested in this study contain merely a part of the entire known bouquet of attractive components of the I. typographus aggregation pheromone (Table 1). The reason for this is their main application in the monitoring of the species [13,32,71,91], which only requires the attraction of a sufficient number of beetles. The best trapping results were obtained by Typosan ® , which is the only product containing nothing more than the synergistically acting pheromone components cis-Verbenol and 2-Methyl-3-buten-1-ol.…”