Identification the etiology of root and foot rot's causal agents of Brassica napus in Marvdasht (Fars province)

Canola disease is one of the most important challenges in canola production. In different countries, various fungal agents, such as Rhizoctonia solani Pytium sp., Phytophthora sp. and Fusarium sp. have been introduced as root rot and damping off agents of canola. The aim of this study was to identify the fungal agents involving in canola foot and root rot and, to determine the most frequent fungal agent of the infection in Marvdasht region (Fars province). In this study, root and foot rotted plants were collected and their fungal agents were isolated. Sampling was performed in various fields in Marvdasht. Isolated fungi were cultured on PDA and purified on 2% water agar. Identification of fungal specious was carried out by using standard keys. All purified isolates were tested for pathogenicity. In this study, five pathogenic fungi belonging to four genera, Fusarium Rhizoctonia Phoma and Pythium were isolated from diseased samples. Among all isolates, F. solani (25%) and Phoma betae (2.5%) had the highest and lowest frequency, respectively. R. solani was very aggressive, whereas P. aphanidermatum and F. solani had produced very mild disease symptom. Our findings showed that canola root rot caused by R. solani is wide dispersed in Marvdasht region in early growth stages; so we strongly recommend that R. solani anastomosis group be identified in the next study. Moreover, usage of anti-microbial resistance and tolerance variety might be investigated. This is the first report of R. solani existence on canola root in Fars province.