Characterization of new Bipolaris spp.: the causal agent of rice brown spot disease in the north of Iran.
Brown spot is one of the most important seed-borne diseases of rice. It causes qualitative and quantitative damages on rice. Although this disease prevails throughout the rice growing areas of Iran, there is no precise information about its dispersal, species and the rate of damage. A study was conducted to identify the genus and species of rice brown spot agent in Guilan. The isolated pathogens comprised Bipolaris oryzae [Cochliobolus miyabeanus] (10%), B. victoriae [Cochliobolus victoriae] (85%), B. indica (2%) and B. bicolor (3%). Pathogenicity test of the isolates in a desiccator revealed the pathogenicity of the species and their ability to cause brown spot on rice.