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Xeris spectrum

Wood wasp Xeris spectrum

Description

Xeris spectrum is a wood wasp from the family Siricidae, commonly found in coniferous forests throughout Europe, Asia, Africa, and North America. This large wasp, with females measuring up to 28 mm, uses its powerful ovipositor to lay eggs under the bark of coniferous trees, mainly targeting spruce, pine, and larch. The larvae bore into the wood, creating extensive tunnels as they feed, but unlike most Siricidae species, X. spectrum lacks own symbiotic fungi. Instead, it often exploits the fungi associated with other wood-boring wasps. The complete development cycle, from egg to adult, spans several years, with adult emergence taking place in summer.

Symptom

Infested trees exhibit galleries filled with sawdust-like frass. Extensive larval tunneling weakens the wood, reducing timber value. Common especially in damaged or homogeneous conifer stands. In Xeris spectrum, the white spots are distinctive identification markers located on the sides of the prothorax, just behind the eyes. These spots stand out against the generally dark (black or dark brown) shiny body and help differentiate X. spectrum from other similar wood wasps. The white spots, paired with the insect's cylindrical body shape and orange-red legs, provide clear visual cues for identifying this species.

Tree Species: Pine, Fir, Spruce, Larch

Part of a plant- attacked: Tree trunk

Pest significance: Harmful

Pest Category: Insects

Invasive Species: No

Present in EU: Yes