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Sirex Woodwasp

Sirex Woodwasp
Sirex woodwasp
Photograph credit: David R. Lance,

The Sirex woodwasp (Sirex noctilio), a Eurasian native, was first discovered in New York in 2004, in the City of Fulton, Oswego County. This was the first North American discovery of this exotic, invasive pest that is one of the top 10 most serious forest insect pest invaders worldwide. Sirex has caused extensive losses to (non-native) pine plantations across the Southern Hemisphere, in Australia, New Zealand, Chile and South Africa, and has no known, native natural controls.

While the insect continues to be an issue in other parts of the world, we have yet to see major forest damage in New York, and it is now present in most parts of the state. However, DEC continues to monitor NY populations in case its infestations become a greater issue.

Damage and Threats

The female Sirex woodwasp injects a toxic mucus and a fungus while laying eggs in the bark of susceptible pine trees. This typically occurs 10-30+ feet up on pole-sized and larger trees (6-8" in diameter and larger). Trees that are already suppressed or stressed due to other site or environmental conditions seem to be preferred by the female wasps. The mucus quickly kills tree cells from the egg-laying site upwards. The fungus feeds on the killed wood, and the insect larva feed on the fungus.

As they grow, the larvae bore galleries deep into and through the wood, unlike bark beetles, which typically confine themselves to the cambium layer, just under the bark. This makes them more difficult to detect and more difficult to eliminate. These trees are often used to make solid wood packing material. Since the life cycle can take a year or more, the insect is easily transported in pallets or other wood packing material. Based on the conditions of its native range in Europe and Asia, it could establish itself in any climate zone of North America where pine is found.

Areas at Risk

sirex woodwasp on a piece of wood
Photographic credit: Gyorgy Csoka,
Hungary Forest Research Institute,

All pine species are believed to be at risk, particularly stressed Scots (or Scotch) pine and red pine, as well as eastern white pine. Literature indicates the Sirex woodwasp will also attack virtually all our other native softwood species. While there is potential for serious losses to softwood stands in New York, the greater concern nationally is if this invasive, exotic pest makes its way into the vast plantations of susceptible pine species found across the Southern US region. Pines in that region are typically found in large, homogenous, commercial plantations. This is far different (and far more susceptible to serious mortality) than the pine distribution in NY forests. Here, forest tree species are more varied and highly-susceptible pines make up a smaller and more scattered component of our forests.

What You Can Do

If you think you have found Sirex woodwasp, try to capture the insect so you can take a photo and email it to DEC's Forest Health team, or call the Forest Health Information Line at (866) 640-0652. Keep the insect in a container in your freezer in case it is a Sirex woodwasp. Identification from a photo can be difficult and the species will need to be confirmed by a lab. Please also report any major pine damage you find in New York forests.