Scientific Name: Sirex noctilio

What Is It?

The Sirex woodwasp is a species of wasp native to Eurasia and northern Africa. It primarily attacks pine trees (sometimes also spruce and fir trees), laying its eggs along with a symbiotic fungus and toxic mucus that kill the tree. The larvae tunnel through the wood, eventually emerging as adults.

Is It Here Yet?

No, but established populations reside in the eastern United States.

Why Should I Care?

Native woodwasps only attack dead or dying trees, but Sirex woodwasps will attack healthy trees. Populations of Washington’s native pines and other conifers could suffer severe damage from an infestation of Sirex woodwasps.

How Can We Stop It?

Sirex woodwasp was introduced through imported wood products. Avoid moving firewood far from the area where you bought it— buy it where you burn it.

What Are Its Characteristics?

  • 0.5-1.5 inches long as an adult.
  • Cylindrical body, spear-shaped plate at the end of the abdomen, black antennae.
  • Females: metallic blue head and body, orange legs, long spikey ovipositor (resembles a stinger).
  • Males: metallic blue head and thorax, orange and black abdomen.

How Do I Distinguish It From Native Species?

There are many native species of woodwasp that look very similar to Sirex woodwasps. Species are best identified by an entomologist. If you have a suspected Sirex woodwasp, contact your local Washington State University Extension agent, the Washington State Department of Agriculture, or the Washington Department of Natural Resources.

Additional Photographs