a survey of sclerogenic fungal pathogens of rice plant (oryza sativa l.) in guilan province

abstract sclerogenic fungal pathogens, are among the most important diseases of rice plant. sheath blight caused by rhizoctonia solani is one of the economically important diseases that attack a wide range of hosts. stem rot (magnaporthe salvinii) has also been found with different severity in most fields of guilan province. to determine sclerogenic fungal pathogens of rice plant, 141 isolates around guilan province were collected and taxonomically studied. four species viz r. solani kuehn, r. oryzae- sativae (mordue) sawada, sclerotium hydrophilum saccardo and magnaporthe salvinii (catt.) krause and webster (sclerotium oryzae catt.) were identified. sclerotium hydrophilum saccardo and r. oryzae- sativae (mordue) sawada are new for iran and guilan province mycoflora, respectively. although s. hydrophilum was reported as a pathogen on rice, we could not be able to verify pathogencity of this species in laboratory conditions according to kokh's postulate. pathogenecity tests showed that the other three species are pathogen on rice plant.