Growth of the Sirex-parasitic nematode Deladenus siricidicola on the white rot fungus Amylostereum

Abstract

The Kamona strain of the nematode Deladenus siricidicola has been extensively used as a biological control agent against invasive Sirex noctilio woodwasps in the Southern Hemisphere, where it sterilizes female hosts. In North America, a non-sterilizing (NS) strain of D. siricidicola, thought to have been introduced with S. noctilio, is commonly found parasitizing this invasive woodwasp. Species of Deladenus that parasitize Sirex have a parasitic form, as well as a mycophagous form. The mycophagous form feeds on Sirex fungal symbionts in the genus Amylostereum. The goal of this study was to compare reproduction of NS and Kamona D. siricidicola when feeding on four isolates of Amylostereum areolatum (three introduced and one native in North America) and one native strain of Amylostereum chailletii isolated from Sirex nigricornis. Mycophagous forms of the two D. siricidicola strains displayed relatively similar production of offspring when feeding on most of the A. areolatum found associated with S. noctilio in this continent, except for strain BD on which NS produced more offspring than the biological control strain Kamona. Growth of both nematodes was greater on the introduced versus the native A. areolatum isolates.

Keywords: Biological control; Fungal-feeding nematode; Invasive arthropod; Sirex noctilio; White rot fungus.