Identification and Pathogenicity of Fungi Species Causing Root Rot in Pepper in West Azarbaijan Province

Pepper root and crown rot was investigated during 2006-2007 in West Azerbaijan province. Pepper fields were checked in Orumieh، Mahabad، Miandoab، Oshnavieh and Piranshahr in August and September. Infected plants with their soils were sampled and transferred to the laboratory immediately. In order to isolate fungal agents، acidic PDA، PCA and CMA cultures were used and for pseudo-fungal agents، baiting method was applied in infected soils. Then، isolates were identified at species level using selective culture media. Eighty two isolates were taken from the infected plants and soils and were subjected to a taxonomic study. These isolates were related to Phytophthora capsici، Pythium aphanidermatum، Rhizoctonia solani، Fusarium oxysporum،F. solani، F. clamidosporum، F. sambucinum and Verticillium dahliae. Patogenicity test was carried out in greenhouse on 34 selected isolates for two pepper varieties (Bell and Local variety) in West Azarbaijan and percentage of the infected plants was calculated after a definite time from inoculation، depending on fungi species. Among the selected isolates، isolates from F. sambusinum and F. chlamydosporum had no pathogenicity effect on two pepper cultivars. It is noted that pathogenicity of F. solani on the local variety was very low. According to Koch rules، pathogens were isolated again from infected plants.