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History and management of sirex wood wasp in pine plantations in New South Wales, Australia.

2005; Springer Science+Business Media; Volume: 35; Issue: 1 Linguagem: Inglês

1179-5395

Angus J. Carnegie, R. H. Eldridge, D. G. Waterson,

Ecology and Vegetation Dynamics Studies

Sirex wood wasp (Sirex noctilio Fabricius (Hymenoptera: Siricidae)) is one of the most important insect pests of Pinus radiata D. Don in Australia. Forests NSW manages over 195 000 ha of P. radiata, and is the largest pine grower in Australia. Sirex was first detected in New South Wales in 1980 at Albury, and within 10 years was established in the pine-growing areas of Hume (Tumut), Monaro (Bombala), and Macquarie (Bathurst) regions. It reached northern region (Walcha) in 1997 and spread slowly up to Tenterfield, 25 km south of the Queensland border, by 2002. Although sirex emergence holes were observed in several trees in a plantation near Casino in 2002, no larvae or adults were seen, and no further evidence of sirex was observed, so we do not believe it has established in this area. The northward spread of sirex was assisted by the large pine-growing regions around Tumut, Bathurst, Walcha, and Glen Innes, and smaller private plantations and woodlot and windbreak plantings. Sirex is expected to reach the P. radiata plantations in south-eastern Queensland, and the southern-pine plantations in coastal north-eastern New South Wales, by 2008. Sirex management in this State began in 1981, consisting of releases of biological control agents, surveillance, and silvicultural regimes, and continues today. The sirex nematode, Beddingia (=Deladenus) siricidicola Bedding, provides the most effective control of sirex in New South Wales. Of the six species of parasitoid wasps released in the State since 1980, Ibalia leucospoides Hochenwarth and Megarhyssa nortoni (Cresson) are the only ones regularly detected in sirex-struck trees. Ibalia leucospoides and M. nortoni have been detected in all pine-growing regions in New South Wales, with I. leucospoides having the highest level of parasitism. Damaging outbreaks of sirex in New South Wales, where more than 3% of trees in an area are killed, have mainly been confined to localised areas less than 200 ha, in unthinned stands with trees 10–25 years old, where a biological control programme was not conducted for several years, or in snow-damaged areas. Pinus radiata is the species most susceptible * Corresponding author: angusc@sf.nsw.gov.au. 4 New Zealand Journal of Forestry Science 35(1) to sirex, although a heavy infestation in P. taeda Linn. observed near Walcha was the first record of this species as a host of sirex in Australia. The annual sirex management programme in Forests NSW, consisting of biological control, forest health surveillance, and silvicultural treatment, has reduced the economic impact of this potentially damaging pest in New South Wales.