اولین گزارش Phytophthora cinnamomi به عنوان عامل بیماری پوسیدگی طوقه و ریشه درختان گردو(Juglans regia) در منطقه سیرچ استان کرمان

Phytophthora, causes huge economic loss to many plant species all over the world, annually. The study of symptoms such as reduced growth in young seedlings and trees, yellowing of leaves, crown and root rot, and complete death and deterioration of walnut trees around the world has led to the identification of different species of this fungus-like microorganism. The identified species include P. cinnamomi, P. cactorum, P. cambivora, P. citricola, P. cryptogea, P. nicotianae, P. chlamydospora, P. inundata . Moreover, Phytophthora cinnamomi is known as one of the most destructive plant pathogen in different continents. During surveys in Iran, species such as P. cactorum, P. citricola and P. citrophthora have been isolated and identified from the southern region of the country on walnut. In 1402, after observation of decline on few walnut trees in Sirach region of Kerman province, 7 samples were taken from the soil, crown and roots. Further studies were carried out by baiting, isolating and investigating samples on specific culture media. Pure cultures were obtained and morphological studies were confirmed that the causal agent belongs to Phytophthora sp. Molecular identification were done by sequencing the ITS rDNA region and led to identification of P. cinnamomi. The pathogenicity test was performed through walnut cut-stem under-bark inoculation assay, and production and extension of lesion were recorded after 2 weeks. To our knowledge and based on the literature, this is the first report of P. cinnamomi as the causal agent of crown and root rot of walnut trees in the south-east of Iran from Sirch region in Kerman province.