23. Graphiola leaf spots (False Smut) (Graphiola phoenicis) – a new disease of palms in Bulgaria (Brief communication)

A new type of disease symptoms were discovered on palms grown in hotels and private homes in the region of Bourgas – Sunny Beach, in 2011. They are typical of Graphiola leaf spots, known also as “false smut „ due to specific sporulation. The initial symptoms are very tiny yellowish to dark-brown or black spots (0.3-0.8 mm), sometimes with a chlorotic hallo. The typical spots are necrotic, 3-5 mm. On those spots fungus forms cup-shaped, brown to black “sori”, 0.06-0.08 mm, rupturing the epidermis. As the sori mature, spores are produced in chains, and also filamentous sterile hyphae, light in color. The spores are light yellow spherical to ellipsoid, 3-5 μm, with thick cell-walls. After the spore dispersal the sori appear as a black crater. The causal agent is identified as Graphiola phoenicis based on disease symptoms and morphological characteristics of fruiting bodies and spores.