Two new Ascomycetes on twigs and leaves of Silver birches (Betula pendula) in Estonia
Cryptosporella betulae (Gnomoniaceae, Diaporthales) and Pleomassaria siparia (Pleomassariaceae, Pleosporales), the first both in teleo- and anamorphic (Disculina betulina), the second only in its anamorphic stage (Prosthemium betulinum) are recorded for the first time in Estonia. In summer 2008 first disease symptoms were observed; in summer 2009 C. betulae was identified as a new species and as an obvious pathogen, causing these symptoms on young Silver birches (Betula pendula). At the following winter both anamorphic fungi were found abundantly sporulating on thin branches and twigs, fallen into the snow from mature Silver birches. In May 2010 the teleomorphic C. betulae was first time recorded on the birch leaves, fallen last autumn. Pathogenicity of P. betulinum is still not known. Taxonomic relevance of the fungi together with the possible connection of the findings with the recent meteorological extremities in Estonia is shortly discussed.