Isolation, Identification and Biomanagement of Root Rot of Black Cumin (Nigella sativa) Using Selected Bacterial Antagonists

Abstract

The study deal with potentiality of some bioagents for controlling the root rot of black cumin under greenhouse conditions, caused by Fusarium spp. Eight fungal isolates were obtained from diseased of back cumin plants collected from Assiut Governorate. These isolates were belonged to the genus Fusarium spp. They were identified as, four isolates of F. comptoceras, three isolates of F. solani and one isolate Fusarium lateritium. Pathogenicity tests indicated that all tested fungal isolates were able to infect black cumin plants causing symptoms of root rot resulted in dwarfism and death before the capsules mature. They varied in their pathogenicity, Fusarium comptoceras No.1 gave the highest percentage of disease severity and percentage of infection on black cumin plants (53 and 50% respectively), while isolates F. comptoceras Nos. 3 and F. solani No. 6 gave the lowest percentage of infection (15 and 17% respectively) the rest of isolates showed moderate of percentage of infection. Antagonistic capability of 15 isolates (PGPR) was tested in vitro against growth of three isolates of Fusarium spp. the causal pathogen of root rot of black cumin. Seeds black cumin plant treated with all bioagents as a suspension significantly increased the root dry weigh and foliar dry weigh compared to infected control. In conclusion, our study confirmed that used of bioagents may be applied as future ecofriendly alternatives to synthetic fungicides for controlling the disease of black cumin.