Overview
Female sirex woodwasps oviposit into standing or freshly felled
Pinus
logs, simultaneously injecting an egg, mucus-like oviposition fluid and fungal spores. The developing larvae then feed on the mycelia of the wood-rotting fungi. Susceptible trees can be killed by a combination of the action of the fungus and
Sirex
feeding. A number of exotic siricid species are frequently encountered as quarantine intercepts. A recent incursion into New South Wales is
Tremex fuscicornis
, a species of Palaearctic origin.
Description
Adults are 10 44 mm long with a cylindrical body. Females have a metallic blue head and body with orange legs, and a spike-like projection on the posterior abdominal tergum that protects the ovipositor when it is not being used for egg-laying. Males are smaller than females, have a metallic blue head and thorax, an abdomen that is orange at the centre with black at the base and posterior end, hind legs that are thickened and black, and a pointed posterior sternum.
Distribution
This family (horn-tailed wasps) of more than 90 species has a northern hemisphere distribution, and is naturally absent from the Australasian region. The sirex woodwasp (
Sirex noctilio
), a native of Europe, Asia and northern Africa, has been introduced accidentally into many forestry regions of the world, including south-eastern Australia and New Zealand where it is a pest of introduced conifers, especially the plantation pine,
Pinus radiata
.
Further information about the Siricidae can be found in Goulet 1993 and Naumann 1991.