Release of parasitoids for Sirex noctilio control by transporting infested logs

Summary

The Woods & Forests Department of South Australia released Megarhyssa nortoni by distributing infested logs throughout its southeastern region during October 1988. Logs were transported from a compartment known to have a high density of M. nortoni to 143 release sites. An estimated 18 000 female M nortoni emerged from these logs from October to December.

Rhyssa hoferi, Rhyssa persuasoria, and Schlettererius cinctipes were found to be established in another plantation, but releases by transporting logs were not practical because densities of these species were too low. Techniques that may increase the parasitoid density within trees are suggested.

A strategy for releasing parasitoids should include log transport, in addition to the release of adult parasitoids obtained from insectary cultures or from field-collected logs.

Key words:

• Sirex noctilio
• Megarhyssa nortoni
• biological control
• forest pest management