Distribution and characterization of Dothistroma needle blight pathogens on Pinus mugo in Slovakia

The occurrence and distribution of Dothistroma needle blight (DNB) on Pinus mugo was studied in 2014–2015 around the Slovakia. In total, 42 localities were investigated both native and planted ones. Symptoms of DNB were observed on 35 localities only on planted shrubs. All these 35 localities are new P. mugo DNB stands. No DNB symptoms were observed in natural and naturally regenerated plantations. DNA was extracted from a total of 236 isolates and eight needle samples. Based on the ITS-rDNA comparisons and using species specific primers, both pathogenic Dothistroma species were detected: D. septosporum and D. pini. Isolates of D. septosporum had ITS sequences identical to D. septosporum from Europe and both mating types were identified with slight predominance of MAT2. The ratio of D. septosporum mating types varies significantly between sites, ranging from an equal proportion of each mating type to single mating type populations. D. pini ITS sequence grouped with D. pini from Ukraine, Russia and Switzerland and only MAT2 was found.