وقوع بیماری لکه‌برگی ازگیل ژاپنی از Alternaria alternataدر شرق استان مازندران

Japanese parsnip (Eriobotrya japonica) has been cultivated for more than 2000 years. Various diseases threaten the production of this fruit. Leaf spot disease and fruit rot in this tree in Iran was first reported by Mirhosseini et al. in 2014. The aim of this research is to identify the agent of Japanese parsnip leaf spot disease using morphological and molecular characteristics in different cities of eastern Mazandaran province. Sampling was done in the spring of 1402 from different cities of the province. The symptoms were observed in the leaves of Japanese parsnip trees in the form of small, circular and brown necrotic spots. The spots gradually became wider and later became irregular in shape or remained circular with concentric rings. From the cultivation of samples with symptoms in PDA (Potato Dextrose Agar), a number of 11 fungal isolates were selected for different investigations. The pathogenicity of the selected isolates was performed on healthy leaves. A number of isolates were close to symptoms one week after infection observed from the infected trees caused spots. ITS1 and ITS4 primers were used for the amplification of the region (Internal transcribed spacer). The morphological characteristics of the colonies and spores produced in the isolates were consistent with the characteristics of Alternaria alternaria The amplified fragment product after sequencing and blasting in the gene bank showed more than 98% similarity of the isolates with A. alternaria.