Adult Description: Woodwasps (or horntails) are large, robust insects, usually 1.0 to 1.5 inches long. Adults have a spear-shaped plate (cornus) at the tail end; in addition females have a long ovipositor under this plate. Body dark metallic blue or black; abdomen of males black at base and tail end, with middle segments orange. Legs reddish-yellow; feet (tarsi) black; males with black hind legs. Antennae entirely black. Positive identification of S. noctilio needs to be confirmed by an insect taxonomist.
Larva Description: Larvae are creamy white, legless, and have a distinctive dark spine at the rear of the abdomen. More than a dozen species of native horntails occur in North America. No keys to identify woodwasp larvae to the species level have been developed
Host Plant: Monterey pine (P. radiata) and loblolly pine (P. taeda). Other known susceptible pines include slash (P. elliottii), shortleaf (P. echinata), ponderosa (P. ponderosa), lodgepole (P. contorta), and jack (P. banksiana).
Ecological Threat: In these Southern Hemisphere countries, sirex woodwasp attacks exotic pine plantations, and it has caused up to 80 percent tree mortality. Most of the plantations are planted with North American pine species.
Biology: Scientists estimate that S. noctilio can spread at least 25 miles per year naturally.
History: This woodwasp was introduced inadvertently into New Zealand, Australia, Uruguay, Argentina, Brazil, Chile, and South Africa. In these Southern Hemisphere countries, sirex woodwasp attacks exotic pine plantations, and it has caused up to 80 percent tree mortality. Most of the plantations are planted with North American pine species.
U.S. Habitat: Forested areas especially in areas of pines.
Native Origin: Sirex woodwasp is native to Europe, Asia, and northern Africa.
U.S. Present: Twentyfour counties in upstate New York and two counties in Pennsylvania have positively confirmed the presence of this pest.
More than a dozen species of native horntail wasp.
Currently no management. Collect and submit any suspect woodwasps to your county extension or state Department of Agriculture office.
Dennis A. Haugen & E. Richard Hoebeke. 2005. Pest Alert: Sirex Woodwasp - Sirex noctilllio. USDA Forest Service. Accessed 05 January 2012: http://na.fs.fed.us/spfo/pubs/pest_al/sirex_woodwasp/sirex_woodwasp.htm.