DETERMINATION OF Pestalotiopsis sp. CAUSING DISEASE ON FRUIT CLUSTERS IN HAZELNUT GROWING AREAS OF ORDU, GİRESUN AND TRABZON PROVINCES IN TURKEY

Turkey is the leader in the production and export of hazelnuts. Hazelnut production in Turkey in the Black Sea Region extends from the east of the Georgia border to Istanbul. In this study conducted in hazelnut growing areas in Ordu, Giresun and Trabzon provinces in Black Sea Region between 2008-2009, determination of Pestalotiopsis sp. causing disease on fruit clusters and isolation rate of the agent in these provinces, was investigated. Surveys were carried out on total 95,600 fruit clusters corresponding a field of 1555.5 da in July-August. The most predominant symptom was determined as blight. The incidence of Pestalotiopsis sp. was found as 6.28% in Ordu, 7.33% in Giresun and 7.41% in Trabzon. The agent was isolated from symptoms of cluster blight and fruit necrosis with highest rates. Species identification was done according to the basis of culture and conidial morphology, growth rate and rDNA sequences. The pathogenicity tests using detached leaf and fruit clusters revealed various rates of disease severity for the isolates in the genera of Pestalotiopsis. Disease severity was 37.5-100% on detached leaves, 66.7% on severity of disease on detached twigs and clusters in pathogenicity tests.