Status and management of insect pests and diseases in Victorian softwood plantations

Summary

Insect pests and diseases destructive to Pinus radiata and other exotic conifers in State-owned plantations (approximately 100 000 ha) and in pine nurseries are reviewed, as are the control measures for minimizing tree mortality, loss of growth increment and wood degrade. The wood wasp Sirex noctilio and the pine needle blight Dothistroma septospora have caused significant tree mortality and defoliation respectively in plantations, whereas the root rot fungus Phytophthora cinnamomi and the root lesion nematode Pratylenchus penetrans have been linked to substantial seedling deaths in nurseries. Three species of exotic bark beetle, including Ips grandicollis, are widely distributed in plantations, but none have so far been associated with economically important damage. A range of indigenous defoliating agents have adapted to pine, but outbreaks have usually been localised and of short duration.

The use of direct controls (such as pesticide spraying) and of cultural, biological and genetic techniques is discussed in the context of present and future forestry needs. The threat posed by accidentally introduced insect pests and diseases to Victoria's total public and private commercial pine resource (nearly 200 000 ha) is highlighted. Twelve actions are specified that are considered necessary to achieve rapid identification and control of quarantine escapes important to forestry and the timber industry.