Retrospect, insights and foresights: Biological control of Anobium puntcatum with Spathius exarator

Abstract

Biological control using beneficial organisms is getting more and more important in Integrated Pest Management. An effective strategy in the fight against the most common timber pest species, the furniture beetle Anobium punctatum, is based on the parasitoid wasp species Spathius exarator. This braconid wasp parasitizes its host species by piercing its ovipositor directly through the wood surface followed by oviposition onto the beetle larva. After feeding on the larva and pupation, the adult wasp emerges through a tiny 0.5 mm wide wood hole, which can be clearly distinguished from the 2 mm wide hole of A. punctatum. This enables us to observe easily the treatment success as each new S. exarator exit hole is equivalent to one killed beetle larva. Between 2012 and 2017, the braconid wasps were introduced into about 80 A. punctatum infested buildings. At least twelve treatments over a period of up to three years were performed. On exactly defined areas, the newly emerged exit holes of A. punctatum and S. exarator were counted and the parasitisation rate was calculated. Here we present pooled data of 29 A. punctatum infested churches, successfully treated and monitored over a period of one to five years. Furthermore, as a representative sample, we show the results of one church over a period of six years. We demonstrate the biological control of the common furniture beetle with this braconid wasp as an efficient, sustainable alternative to conventional residual methods. However, after a period of up to three years intensive treatment, a continuous monitoring-program with necessary additional single treatments should follow.

Keywords

• biological control
• wood pest
• cultural heritage
• common furniture beetle
• parasitic wasps