Birch necrotic leaf spots caused by fungal pathogens

Abstract

Microscopic fungi associated with lesions on the leaves of Betula pendula Roth. species growing in different greenery types of Nitra town are causal factors weakening the health state and vitality of these trees. Many of them caused anthracnose and formed small, irregular, circular brown spots with dark brown margins or broad necrotic blotches. Disease symptoms begin as a large spots or blotches, which rapidly widen and join, resulting in large areas of dead tissue. The fungi overwinter on infected fallen leaves. Sporulation begins when spring conditions become warm and wet. During the study of the mycoflora of birch leaves ten fungal species were recorded: Asteroma microspermum, Cryptocline betularum, Discula betulae, Marssonina betulae, Melanconium betulinum, Phoma sp., Phomopsis sp., Phyllosticta betulina, Pyrenopeziza betulicola, Stemphylium sp. In this work were described disease symptoms and some distinctive morphological features.