Which Cyclaneusma minus morphotypes are responsible for needle cast of Pinus spp. in Slovakia?

Abstract

Cyclaneusma needle cast (CNC) is a needle disease which caused deterioration of vitality and reduction in the growth of pines. The disease is caused by the ascomycetous fungus Cyclaneusma minus, which has two well-described morphotypes; C. minus simile and C. minus verum. The distribution and host range of C. minus simile and verum was determined from needle samples and isolates collected throughout Slovakia from 2014 to 2020. Samples from 111 localities, 11 pine host species and 245 trees collected in different types of planting were analysed. It was found, that both morphotypes are present, but C. minus verum is predominantly responsible for CNC in urban and forest plantings in Slovakia. C. minus verum was positively detected in more than 88% of collected samples, whereas C. minus simile was only in four samples from three localities. Morphotype-specific primers were sufficiently sensitive even for new pine-host species. The host range of C. minus simile and C. minus verum was enriched worldwide. C. minus verum was observed in nine host species, whereas C. minus simile was identified only in one. Cyclaneusma niveum was also recorded and its presence was confirmed through DNA sequencing.