As a countermeasure , cultures of the nematode Deladenus siricidicola have been used as biological control to protect trees since the 1980s . This parasite feed on the mycelia of A. areolatum and is therefore a food competitor of wood wasp larvae . Where S. noctilio larvae are present , the parasite infect and sterilize the eggs of female wasps , causing them to be infertile . These infertile females lay infected eggs into new trees and thus spread the nematode . This control method have proven to be relatively successful to combat the Sirex – Amylostereum complex . In the Southern Hemisphere , where the technique have been widely employed , reductions of parasitism levels of 70 % – 100 % have been achieved .