Introduced Pests Outreach Project

Sirex Woodwasp

Woodborer update: Asian longhorned beetle, emerald ash borer, and Sirex woodwasp (March 21, 2007)

(Click on an image below to see the captioned full-size version)
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Scientific Name: Sirex noctilio
Common Names: European Woodwasp, Sirex Woodwasp

Known Hosts:
Sirex noctilio attacks primarily pines, but on occasion it will infest other conifers such as Abies (fir) and Picea (spruce). In its native range (Europe, Asia, and northern Africa), it attacks Scotch (Pinus sylvestris), Austrian (P. nigra), and maritime (P. pinaster) pines. In its introduced range (Australia, New Zealand, South America, and South Africa), it attacks Monterey (P.radiata), loblolly (P.taeda), slash (P. elliottii), shortleaf (P.echinata), ponderosa (P. ponderosa), lodgepole (P.contorta), and jack (P. banksiana) pines.

Key ID Features and Life Cycle:
Adult wasps are 10-44mm (0.5-1.5 inches) long with a cylindrical body. Adults have a spear-shaped plate (cornus) at the tail end. The antennae are entirely black.
Females have a metallic blue head and body with orange legs. A spike-like projection on the tail end of the abdomen protects a female's ovipositor when it is not being used for egg-laying. (Figure 1)
Males have a metallic blue head and thorax. The abdomen is orange at the center with black at the base and tail end. The hind legs are thickened and black. (Figure 2)
Adults emerge from July through September with peak emergence in August. (Figure 3)
Females lay between 20 to 450 eggs after emergence. The female injects a toxic mucus and a fungus when ovipositing that create the proper environment for larval development. (Figure 4)
Larvae are creamy white, cylindrical grubs up to 30 mm (1 1/4 inches) long with a dark spine at the end of the abdomen.(Figure 5)
The larval stage usually lasts for 10-11 months before mature larvae pupate near the bark surface.

Signs of infestation:
The first sign of damage is dripping resin caused by females ovipositing. (Figure 6)
Round exit holes 3-8 mm (1/8 to 3/8 inch) in diameter are visible on trees trunk. (Figure 7)
Serpentine larval galleries within the tree are packed tightly with frass. (Figure 8)
When a tree is infested, foliage wilts then turns from green to yellow to reddish-brown. (Figure 9)

Similar species:
There are 23 native species of siricids in North America. The following publication provides a key for distinguishing those species: Smith, DR and NA Schiff. 2002. A review of the siricid woodwasps and their Ibaliid parasitoids (Hymenoptera: Siricidae, Ibaliidae) in the Eastern United States, with emphasis on the Mid-Atlantic Region. Proceedings of the Entomological Society of Washington. 104 (1): 174-194

Fact sheets and references:
Sirex noctilio information from USDA National Invasive Species Information Center

Sirex noctilio website includes regulatory information and pest alert- Canadian Food Inspection Ageny

Sirex woodwasp information from New York

Sirex noctilio pest alert from the United States Forest Service
HTML page:
pdf file:

Hoebeke, ER, Haugen, DA, and RA Haack. 2005. Sirex noctilio: Discovery of a Paleartic Woodwasp in New York. Newsletter of the Michigan Entomological Society. 50 (1&2): 24-25.

Forestry has a nice collection of Sirex noctilio photos of the wasp, damage, and biocontrol efforts

Sirex woodwasp information from Texas

last reviewed December 18, 2014

Massachusetts Department of Agricultural Resources
Massachusetts Introduced Pests Outreach Project is a collaboration between the Massachusetts Dept. of Agricultural Resources and the UMass Extension Agriculture and Landscape Program. This website was made possible, in part, by a Cooperative Agreement from the United States Department of Agriculture's Animal and Plant Health Inspection Service (APHIS). It may not necessarily express APHIS' views.