Sirex noctilio control program in response to the 1987 Green Triangle outbreak

Summary

In 1987, 1.8 million tree deaths resulted from a Sirex noctilio outbreak in Pinus radiata plantations in southeastern South Australia and southwestern Victoria. The major response was to inoculate 147 000 trees with the parasitic nematode Deladenus siricidicola. Also, projects to salvage sirex-infested trees and to release the parasitoid Megarhyssa nortoni were implemented. The inoculation program cost $1.3 million. Productivity and costs were calculated for the seven procedures used to introduce the nematode. Efficiency was increased by using machines to fell and delimb the trees and by redesigning the inoculation hammer. Knowledge gained from this outbreak should prompt a review of the control recommendations. Forest managers should implement a rigorous control program, as soon as sirex is detected in a region, to minimise the risk of a future outbreak. Key words: Sirex noctilio, Deladenus siricidicola, biological control, forest pest management, Pinus radiata.