Indian mustard (Brassica juncea): A potential fungicide for control of early blight (Alternaria solani) of potato

摘要

Early blight of potato in India causes yield losses from 10-90% in mild to severe infestation. Different combinations of Brassica juncea oil meal were compared for their volatile compound in hydrated form that was fungicidal to Alternaria solani.Indian potato (Solanum tuberosum) variety Kufri Jyoti was selected as an indicator crop for the treatment of Alternaria solani.Among the samples tested the volatile substrate in the oil meal of mustard (Brassica juncea (L.) Coss. & Czern.) with 50% carrier showed the strongest fungicidal effect. Allylisothiocyanate was the predominant fungicidal compound detected in the hydrated oil meal of all treatments. Among 6 carrier combinations tested for seed treatment with ground mustard oil meal, carrier-5A (C-5A)containing Indian charcoal trema (50%), calcium carbonate (1%), barley flour (30%), rice bran (10%) and gum arabic (9%) was the most effective for the seed treatment at 1:1 oil meal and carrier ratio. Seed potato treated with a mixture of mustard oil meal and Carrier-5A ( 1:1) at 7% (w/w) resulted in a significant reduction in incidence of Alternaria solani with no harmful effects to the germination of treated seeds. Effective control of Alternaria solani by the seeds treatment with Carrier-5A mixture was also obtained in a large scale experiment conducted on a field level. This study suggests that the mustard oil meal and carrier-5A (C-5A) mixture has potential for use in the commercial seed treatment for early blight of potato.