SIREX WOODWASP: BIOLOGY, ECOLOGY AND MANAGEMENT Dennis A. Haugen USDA Forest Service, Forest Health Protection, 1992 Folwell Ave., St. Paul, MN 55108 ABSTRACT Sirex woodwasp (Sirex noctilio F.) is an aggressive cyaneus (may be introduced to Europe). All of nonnative woodwasp that kills pine trees. In these species have conifers as hosts, with varying the southern hemisphere, it has caused up to ranges of pine, spruce, fi r, larch, and other 80 percent mortality in unthinned, overstocked conifers (Krombein et al. 1979). However, these pine plantations. In its native range of Europe, North American species use a different species of northern Asia, and the northern tip of Africa, fungus (A. chailletii) than S. noctilio (Bedding and sirex attacks mainly pines (e.g., Pinus sylvestris, Akhurst 1978). P. nigra, P. pinaster), but it is rarely a pest Management of sirex can be accomplished (Spradbery and Kirk 1978). In the Southern through survey, silviculture, and biological Hemisphere, it has attacked many of the pines control. Early detection is critical for successful that are native to North America (e.g., P. radiata, sirex management. The National Strategy for P. taeda, P. elliottii, P. banksiana, P. ponderosa, Australia states that sirex should be detected P. contorta). before any compartment reaches 0.1 percent tree Sirex is expected to have one generation per mortality (Haugen et al. 1990). Trap trees are a year over most of North America, with adult very effi cient and effective monitoring tool in the emergence from July through September. southern hemisphere. Its application in North Females lay eggs into the wood (up to 400 America will need to be tested due to the native eggs per female) and also inject a fungus bark beetles and woodborers that may compete (Amylostereum areolatum) and toxic mucus for these trap trees. A detection trap may be during oviposition. Together, the fungus and feasible, but more research in needed on lures mucus kill the tree, and sirex larvae feed on (i.e., host volatiles) and trap design. Silvicultural the fungus as they develop. Early symptoms of control by on-time thinning will need to be attacked trees include resin beads or dribbles considered in pine plantations and dense fi re- at the oviposition sites, brown cambial staining, regenerated stands. and green needles that refl ex. Later symptoms Another key to sirex management is a parasitic include foliage that turns light green to yellow to nematode (Deladenus siricidicola). It is highly red, larval galleries with tightly packed fi ne frass, density dependent and specifi c to woodwasps and round exit holes that range from with the fungus A. areolatum. The use of this 3-11 mm in diameter. nematode for sirex control will be presented by Seven native sirex species occur in North America Dr. Robin Bedding (See page 21). However, it is (S. areolatus, S. behrensii, S. cyaneus, S. edwardii, important to note that the North American sirex S. juvencus, S. longicauda, and S. nigricornis). species also have parasitic nematodes (Deladenus However, there are some uncertainties with canii, D. nevexii, D. proximus, and D. wilsoni), and S. juvencus (may be Paleartic in origin) and S. these nematodes require the fungus A. chailletii 48 Proceedings—Interagency Research Forum on Gypsy Moth and other Invasive Species (Bedding and Akhurst 1978). Also for biological Haugen, D.A., R.A. Bedding, M.G. Underdown, control, parasitoids have been introduced into F.G. Neumann. 1990. National strategy sirex woodwasp populations in the southern for control of Sirex noctilio in hemisphere, and most are native to North America Australia. Australian Forest Grower. 13(2): (e.g., Megarhyssa nortoni, Rhyssa persuasoria, special liftout section No. 13. 8 p. Rhyssa hoferi, Schlettererius cinctipes, and Ibalia Haugen, D.A. and E.R. Hoebeke. 2005. Pest leucospoides), so parasitoid introductions for Alert: Sirex woodwasp—Sirex noctilio sirex management should not be needed in North F. (Hymenoptera: Siricidae). USDA Forest America (Haugen and Hoebeke 2005). For the Service, Northeastern Area. NA-PR-07-07. USDA Forest Service Pest Alert on sirex woodwasp, go to: www.na.fs.fed.us/fhp/sww/ Krombein, K.V., et al. 1979. Catalogue of Literature Cited Hymenoptera in America north of Mexico, Vol. 1, (Symphyta and Apocrita). Washington, Bedding, R.A. and R.J. Akhurst. 1978. DC, Smithsonian Institution Press. Geographical distribution and host Spradbery, J.P., A.A. Kirk. 1978. Aspects of the preferences of Deladenus species (Nematoda: ecology of siricid woodwasps (Hymenoptera: Neotylenchidae) parasitic in Siricidae) in Europe, North Africa and Turkey siricid woodwasps and associated with special reference to the biological hymenopterous parasitoids. Nematologica. control of Sirex noctilio F. in Australia. 24: 286-94. Bulletin of Entomological Research 68: 341-359. Proceedings—Interagency Research Forum on Gypsy Moth and other Invasive Species 49.