Live Sirex wasp posing for shot for Canberra Agricultural show . Taken with the Hasselblad at ACT Forests last century! We had a program of growing millions of the nematodes to prey on the wasps. The wasps were killing off our pines, which we could map from aerial photography, and on the ground. We had tups of the nematodes, and sent teams out to inject the trees. The little wasps camp along and got infected when they drilled into the tree to lay eggs. see good old Wikipedia.. en.wikipedia.org/wiki/Sirex_noctilio
Several biological control agents have been employed to limit populations of the sirex woodwasp. A nematode, Deladenus siricidicola, has shown to infect up to 70% of the wasps, but delivery and inoculation have been an issue when it comes to delivering the organism to the tree. There have also been several introductions of parasitic wasps. Megarhyssa nortoni nortoni, Rhyssa persuasoria persuasoria and Ibalia leucospoides leucospoides have been successful at hyperparasitism but do not reduce wasp populations below 40% of the local population. Although some success in slowing the population growth of the wasp has been observed, these measures are not stopping the spread of the wasp.