Impact of Amylostereum (Basidiomycota: Russulales) diversity on Deladenus (Nematoda: Neotylenchidae) behavior and fitness

•Biological control of Sirex noctilio in North America with Deladenus is explored.•The woodwasp’s symbiotic fungus can impact nematode parasitism.•Amylostereum fungus species and strain affected nematode reproduction.•Mycophagous Deladenus juveniles never avoided non-host fungi.•Deladenus proximus could produce some eggs on non-host fungi.