Colorado Exotic Insect Detection and Identification Fact Sheet Series
European Woodwasp/Sirex Woodwasp in Colorado - Identification of Insects and Damage of Similar Appearance
Matt Camper and Whitney Cranshaw
Figure 1. European woodwasp larva tunneling in heartwood. Photo courtesy of Dennis Haugen
Figure 2. European woodwasp adult (female). Photo courtesy of David Lance
The European woodwasp (Sirex noctilio) (Figure 2) is a wood boring horntail wasp (Family Siricidae) of European origin that recently was identified as being established in the midAtlantic region of the US. This insect is primarily attracted to trees that are stressed or in decline but healthy trees can also be attacked. Damage that the insect produces is partly related to wood tunneling by the larvae but more importantly the European wood wasp spreads a fungus (Amylostereum areolatum) that produce a white rot which can seriously weaken the wood.
Through accidental introduction the European woodwasp has extended its native range of Europe, North Africa and western Asia. Presently it is now established in parts of New Zealand, Australia, Uruguay, Argentina, Brazil, Chile and South Africa. Cultivated pine plantations in these areas where the insect was introduce often consider the European wood wasp to be a key pest and have seen significant tree mortality (c.a. 80%) due to infestations.
European wood wasp has frequently been detected at United States ports-of-entry within solid-wood packing materials, but its recent (2004) detection in upstate New York pine trees is the first evidence of North American establishment. Subsequent detection surveys have confirmed its presence in 25 New York counties and 2 counties in Pennsylvania. In 2005, the European wood wasp was detected in 6 locations of southeastern Ontario
Currently, there have been no detections of the European woodwasp in Colorado but this insect has the potential to spread and ultimately become a pest of North American pines over widespread areas of North America. Its spread into Colorado could occur through introduction of packing material originating from Europe, or by movement of infested pine logs or firewood that originate from European woodwasp infested areas of the US. All North America pines are considered vulnerable including jack (Pinus banksiana), loblolly (P. taeda), lodgepole (P. contorta), Monterey (P. radiata), ponderosa (P. ponderosa), shortleaf (P. echinata) and slash (P. elliottii). There are European reports of this insect found associated with spruce, larch, fir and Douglas fir.