Functional roles of nematodes associated with the walnut twig beetle and eastern black walnut in the inland northwest

Beetles (Scolytinae) form intimate associations with a taxonomically and functionally diverse suite of nematodes that are phytopathogens, fungal feeders, entomoparasites. Despite their ubiquity, the ecological significance in lifecycles economically important bark ambrosia beetle species (Curculionidae: Scolytinae) associated plant diseases remains largely unexplored. Thousand cankers disease (TCD) is caused by walnut twig (WTB, Pityophthorus juglandis Blackman) fungus Geosmithia morbida (Kolařík, Freeland, Utley & Tisserat; Ascoymycota: Hypocreales) causes foliar senescence, progressive crown dieback, mortality black (Juglans nigra L.) throughout western North America. In this study, recovered from P. J. Idaho (ID) Washington (WA) were identified morphologically constructing multilocus phylogenies to infer taxonomic relationships taxa for which molecular data available. We conducted assays determine extent feed reproduce on G. other fungi commonly found galleries juglandis. Inoculation experiments effect area subdermal necrotic lesions (cankers) branches mature stems seedlings. The phoretic nematode Bursaphlenhus (Ryss, Parker, Alvarez-Ortega, Nadeler Subbotin) was frequently under elytra WTB all locations, free-living (Panagrolaimus sp.) also widespread trees. Both B. Panagrolaimus sp. reduced size seedlings trees, respectively. However, these may play opposite roles as synergists antagonists based observation exudates and/or microbiota sp., but not destroyed colonies culture. Furthermore, contributed symptoms inoculated morbida. An entomoparasitic (Aphelenchoididae), most closely resembling an Ektaphelenchus haemocoel WTB. Infection rates positively related population sizes inferred emergence rates. Ditylenchus incubated wood WA Rhabtidolaimus ID. community ID differed substantially what has been observed its native range.