First report of hazelnut kernel rot caused by Eremothecium cymbalariae in Bulgaria.

Expansion of hazelnut (Corylus spp.) cultivation in Bulgaria has led to an increased interest in any attendant disease. In the district of Plovdiv during the post-harvest storage periods of 2015 and 2016 shriveled nuts of the cultivars Tonda Romana (C. avellana) and Early Trapesund (C. maxima) were observed. Nuts originating in three locations displayed necrotic pellicles and sunken moldy surface lesions followed by dry rot. Microscopic observations revealed the presence of septate, dichotomously branched and undulating mycelium, and of hyaline, solitary, terminal and fusiform asci that had a rostrum-like apical appendage. Asci 41.6 (40.0-43.3) x 15.4 (11.7-18.3) μm, n=50, usually contained eight uninucleate, slightly bent, wedge-shaped, elongate with one end obtuse and the other end gradually attenuating into a fine point, hyaline ascospores sized 17.6 (16.6-18.3) x 3.0 (2.5-3.3) μm, n=50. Symptomatic pellicles and seeds were plated on potato dextrose agar (PDA), and incubation at 25°C resulted in slow-g...