New regional records of Dothistroma needle blight pathogens from Slovakia: distribution, hosts and pathogens characterization

Abstract

Dothistroma needle blight is one of the most severe needle diseases of pines caused by two closely related species, Dothistroma septosporum and D. pini. The further spread and distribution of this disease were investigated in Slovakia, and new hosts and stand types were identified at the regional level. Dothistroma septosporum was recorded in a natural stand at higher altitude on Pinus cembra in the High Tatras and the P. uncinata records are new host reports for Slovakia for this pathogen. Moreover, for D. pini, P. cembra as a new host at the country level was recorded and P. armandii was identified as new host species worldwide. Mating types for all collected samples and ITS haplotypes for D. pini isolates were determined. For D. pini, five localities with the presence of both mating types and three ITS haplotypes (Dp_HAP.1, Dp_HAP.2 and Dp_ HAP.4) were reported. Samples where both mating types of the pathogens were identified, were selected for the microscopic examination of fruiting bodies aimed to detect sexual reproductive organs. In all inspected needle samples of D. pini, only conidiomata with typical hyaline cylindrical conidia were identified. The sexual state of D. septosporum was recorded in one sample of P. nigra needles.