“…Lophodermium piceae is a cosmopolitan endophyte once thought to be a problematic pathogen of spruce (Gregory & Redfern, 1987), but now considered a weak pathogen at worst, as studies fail to find a strong correlation between poor growth and infection. Both of these species are commonly recorded as endophytes (in their quiescent and saprophytic stages) of the European native Picea abies (Norway spruce), but both have also been recorded on other North American Picea species (Butin, 1986;Carroll & Carroll, 1978;Johnson & Whitney, 1992;Korkama-Rajala, Müller, & Pennanen, 2008;Koukol, Kolařík, Kolářová, & Baldrian, 2012;Lehtijärvi & Barklund, 2000;Livsey & Barklund, 1992;Magan & Smith, 1996;Müller & Hallaksela, 1998Müller, Valjakka, & Hantula, 2007;Müller, Valjakka, Suokko, & Hantula, 2001;Nguyen, Boberg, Ihrmark, Stenström, & Stenlid, 2016;Scattolin & Montecchio, 2009;Sieber, 1989;Stefani & Bérubé, 2006;Suske & Acker, 1989). However, its virulence appears to be variable depending on several factors such as host, host age and climactic factors (Diamandis, 1978;Diamandis & Minter, 1980;Juzwik, 1993;Scattolin & Montecchio, 2009).…”