A to Z of Pests

Exotic Woodwasp

Sirex noctilio

Appearance

• Adult – 20–40mm. Bodies are metallic blue with orange legs.
• Larvae up to 30 mm. They are creamy white and cylindrical with a dark spine at the end of the abdomen.

Lifecycle

• Females lay between 20 and 450 eggs after emerging.
• The larval stage usually lasts for 10–11 months before mature larvae pupate for bout 3 weeks near the bark surface.
• Adults emerge between July and September.
• They have a two year life cycle.

Habits

• This wasp prefers pine trees, but will use spruce, fir, larch, and Douglas fir if necessary.
• Female wasps carry a fungus that they inject into the tree to provision their young. This weakens and will generally kill the tree.