Optimization of Traps Used in the Management of Monochamus galloprovincialis (Coleoptera: Cerambycidae), the Insect-Vector of Pinewood Nematode, to Reduce By-Catches of Non-Target Insects

A possible tactic to survey and control Pine Wilt Disease is the use of semiochemical-baited traps to capture the insect-vector, the pine sawyer Monochamus galloprovincialis (Olivier) (Coleoptera: Cerambycidae). The most common chemical lure used is the Galloprotect Pack, which includes the aggregation pheromone ([2-undecyloxy] ethanol), a host monoterpene (α-pinene), and bark-beetle pheromones (ipsenol and 2-methyl-3-buten-1-ol). This lure also attracts non-target species, including bark beetles (Coleoptera: Curculionidae: Scolytinae) that use ipsenol (Ips sexdentatus (Boerner)) and 2-methyl-3-buten-1-ol (Orthotomicus erosus (Wollaston)) as pheromones, but also large numbers of their natural enemies, Temnoscheila caerulea (Olivier) (Coleoptera: Trogossitidae), Aulonium ruficorne (Olivier) (Coleoptera: Colydiidae), and Thanasimus formicarius (L.) (Coleoptera: Cleridae), and other saproxylic insects (Coleoptera: Cerambycidae). These catches cause a decrease in biodiversity of the forest insect communities, and the removal of predatory insects may favour bark beetle outbreaks. Thus, our project objective was to test trap modifications to try to reduce catches of non-target insects. Modifying the multifunnel trap’s collection cup by placing a 0.5 cm mesh in the drainage hole allowed the escape of all predator beetles (Cleridae, Trogossitidae, Colydiidae, and Histeridae) in 2020, and retained only two Trogossitidae in 2021, against 249 specimens caught in the non-modified collection cup. This simple modification thus allowed the escape of almost all predators, while maintaining the traps’ efficiency at catching the target species, M. galloprovincialis.