Characterization of Deladenus siricidicola (Tylenchida: Neotylenchidae) associated with Sirex noctilio (Hymenoptera: Siricidae) in Canada.

A nematode parasite from recently discovered populations of the invasive wood wasp, Sirex noctilio, in Canada was examined to determine if it was Deladenus siricidicola Bedding, 1968 (Neotylenchidae). The sphaerulariid form of the female was tbund within the haemocoel of the insect adults. Nematode juveniles were reared on several isolates of the symbiotic fungus Amylostereutn areolatwn to obtain the mycetophagous form of the nematode and the pre-adult infective females were induced from those mycetophagous nematodes. The morpholory and morphometrics of the mycetophagous. form and pre-adult infective form matched the description of D. siricidicola. The 18S and ITS of ribosomal DNA, and mitochondrion cytochrome oxidase subunit I (COI) of the nematodes were PCR amplified and sequenced and were close to those sequenced from Australia. Examination of 102 insect specimens from six locations in Ontario indicated that none of the nematode larvae was able to penetrate the .lirer eggs but were stuck inside the egg sheath. This is the first repon of D. siricidicoln in North America and extends the taxonomic characterization and description of this species.