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Sirex (European) Woodwasp

Photo by David R. Lance, USDA APHIS PPQ,

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Common Name: Sirex (European) woodwasp
Scientific Name: Sirex noctilio
Origin: Eurasia and North Africa


Woodwasps (or horntails) are large, full-bodied insects about 1” to 1 1/2″ long. Adult females have dark metallic blue or black bodies with orange legs. The male’s head and thorax are metallic blue, and the abdomen is orange at the center and black at the base. Adults emerge from July to September.


Sirex can inhabit any area containing softwood stands, preying mostly on pine species including scotch, red, and eastern white pine.


While native wood-wasps prey on dead or dying pines, sirex preys on healthy, living pines. Females can inject a symbiotic fungus, toxic mucus, and eggs into the tree. The fungus and mucus work together and kill the tree in a few weeks or months.


Management includes extensive surveys, bio-control research including the use of parasitic nematodes, regulating the transport of wood materials, education and outreach, and applied research.


Wilting, yellowing of the tree crown, resin drops at the egg laying sites, and narrow bands of brownish fungal stain in the outer sapwood.

Regional Distribution


WNY PRISM Priority

Tier 3 – Containment

Invasive Species Priorities – Tier Chart