Dissemination of the mycoparasiteScytalidium uredinicolabyEpuraea obliquus(Coleoptera : Nitidulidae)

摘要

This study aims to identify the role of the beetleEpuraea obliquusHatch in disseminatingScytalidium uredinicolaKuhlman et al., a mycoparasite of western gall rust,Endocronartium harknessii(J.P. Moore) Y. Hiratsuka. The study was conducted in a lodgepole pine,Pinus contortaDougl. var.latifoliaEngelm., stand near Hinton, Alberta. Mycoparasite spores were observed on the integument of adult beetles collected from western gall rust. In field and greenhouse experiments, adult beetles inoculated with spores of the mycoparasite caused significant numbers ofS.uredinicolainfections on western gall rust. SinceE.obliquusadults migrate between galls, the beetle can transfer the mycoparasite from parasitized to unparasitized galls. Scanning electron microscopy showed that spores of the mycoparasite were common on the body of overwintering beetles. It is believed that these overwintering spores are viable because a culture was successfully established from them. This suggests that beetles emerging in the spring can disseminateS.uredinicolato previously uninfected galls.Epuraea obliquusis an important insect vector ofS.uredinicolain western Canada.Key words: mycoparasite, vector, spore dispersal, western gall rust, pine stem rusts.