Deladenus (Tylenchida: Neotylenchidae) reproduction on species and strains of the white rot fungus Amylostereum

Abstract

Deladenus siricidicola nematodes are used for the biological control of invasive Sirex noctilio woodwasps in the Southern Hemisphere. Since the discovery of established S. noctilio in North America and Canada in 2005, a similar biological control program is under consideration in the United States. In this study, a culture of Deladenus nematodes was established from a native Sirex nigricornis woodwasp collected in New York State. These nematodes were identified as Deladenus proximus using molecular and morphometric techniques. D. siricidicola Kamona are mass produced for biological control when feeding on the white rot fungus Amylostereum areolatum in the Southern Hemisphere, so we compared the relative development and reproduction of mycophagous forms of both nematode species when feeding on native and invasive strains of Amylostereum fungus. D. siricidicola Kamona were able to reproduce on all strains of A. areolatum tested, but reproduced poorly on the A. areolatum strain they would be most likely to encounter in northeastern North America, should the nematode be released. Multiple strains of both species of Amylostereum were observed to grow over nematode eggs, preventing them from hatching. D. proximus were able to reproduce well on both Amylostereumchailletii and A. areolatum, despite prior evidence suggesting only A. chailletii is a suitable food source. This is the first report of the ability of D. proximus to survive and reproduce on A. areolatum, the fungal symbiont usually carried by S.noctilio, suggesting this native nematode should be evaluated for its ability to parasitize and sterilize S. noctilio.