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Sirex Woodwasp

Sirex Woodwasp - Sirex noctilio

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. This pest 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.

The female Sirex woodwasp injects a toxic mucus and a fungus while she is laying her eggs in the bark of susceptible pine trees. This typically occurs mid-bole (10-30+ feet up) on pole-sized and larger trees (6-8" in diameter and up). 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 actually 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 its native range in Europe and Asia, it could establish itself in any climate zone of North America where pine occurs.

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 far 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. The pine resource in that region is much more homogeneous, in large, commercial plantations, which is far different (and far more susceptible to serious mortality) than our New York forest conditions, which are more varied, with highly susceptible pines comprising a smaller, and more scattered component of our forests.

If you think you have found Sirex woodwasp, take a photo and email it to the Forest Health team or call (866) 640-0652. Keep the insect in a container in your freezer in case it is Sirex woodwasp. It will need to be confirmed by a lab.

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