Identification and pathogenicity test of some hyphomycetous fungi associated with alfalfa leaf spot disease in West Azarbaijan province

Alfalfa is an important agricultural crop and the most important forage crop in Iran, playing a crucial role in providing feed for livestock. Hephomycetous fungi are considered as part of the factors associated with the leaf spot disease of alfalfa. In this study, according to the importance of alfalfa cultivation in West Azerbaijan province, in November 2020, samples of alfalfa plants with leaf spot symptoms were collected from various farms in the southern regions of this province, including Miandoab, Mahabad and Naghadeh. After direct examination and single-spore isolations from the leaf spots, 66 fungal isolates from different fungal genera were obtained. After growing the isolated fungi on standard culture media and primary morphological identification, molecular analysis of representative isolates was performed using the ITS ribosomal region and or parts of the gapdh gene. Based on morphological and molecular characteristics, eight species belonging to five genera of hyphomycetes including Albifimbria verrucaria, Alternaria atra, Alternaria kordkuyana, Alternari sp. (section Alternaria), Cercospora zebrina, Curvularia inaequalis, Stemphylium botryosum and Stemphilium vesicarium were identified. Following pathogenicity test under greenhouse condition, the pathogenicity of Alb. verrucaria, A. kordkuyana, C. zebrina, S. botryosum and S. vesicarium species was confirmed. Among the identified species, A. atra, A. kordkuyana and Cu. inaequalis are first world records on alfalfa.