Nematode parasites and associates of Dendroctonus spp. and Trypodendron lineatum (Coleoptera: Scolytidae), with a description of Bursaphelenchus varicauda n.sp.

Nematode parasites and associates of four bark beetle species in British Columbia were surveyed. Bursaphelenchus varicauda n.sp., Ektaphelenchus macrostylus, Panagrolaimus dentatus, and Cryptaphelenchus latus were found associated with Dendroctonus pseudotsugae. Parasitorhabditis obtusa was found in the gut and Contortylenchus reversus in the hemocoel of both D. pseudotsugae and D. rufipennis. The latter also had hemocoel infections of Sphaerulariopsis dendroetoni, which were not found concomitant with C. reversus infections. Contortylenchus brevicomi occurred in the hemocoel of D. brevicomis. The first report of a tylenchid larva parasitizing Trypodendron lineatum in North America is presented. Bursaphelenchus varicauda n.sp. was obtained from the gallery frass of D. pseudotsugae. It resembles B. corneolus and B. bestiolus but differs from the former species in female tail shape, the position of the excretory pore, spicule shape, and position of the male caudal papillae, and from the latter species in spicule shape and in the length of the esophagus and postuterine sac.