Distribution and strains diversity of charcoal rot, Macrophomina phaseolina in melon farms of Varamin, Garmsar and Eyvanekey areas

Charcoal rot on melon Macrophomina phaseolina is one of the most important soil borne diseases of melons. The disease has an economical importance throughout the world. So, infested samples from eight sampling points of Varamin Country (south-east of Tehran Province) and Garmsar and Eyvanekey Countries (Semnan Province) were collected, purified and admitted for pathogenicity on melon variety Samsouri. Then, pathogenicity of the sampled strains were compared using susceptible variety of melon, Samsouri. Totally, twelve strains of M. phaseolina were collected from the area with variable pathogenicity; although significant difference was observed among them. Strains MP-SH-34 and MP-SH-37 from Shah Sefid in Eyvanekey country had the highest pathogenicity ability and on the other hand, strain from Davarabad in Garmsar area showed the lowest pathogenicity; so, the strongest and infecting strain was MP-SH-34. According to the results, different strains of M. phaseolina is spread in melon farms of Tehran and Semnan Provinces which is needed to be managed.