Assessment of in vitro Antifungal Prospective of Fungicides against Alternaria alternata, A Causal Organism of Potato Brown Spot and Early Blight Disease

Efficacy evaluation of three fungicides was undertaken against phytopathogenic fungi Alternaria alternata. Fungicide copper oxychloride was found to restrict the growth of fungi at 500ppm concentration, whereas at 5000ppm concentration of benomyl and mancozeb growth of fungi was not occurred. At 1000ppm concentration growth of fungi was fifty percent compare to control on PDA medium. At 5000ppm concentration of copper oxychloride and mancozeb spore germination did not occur. In case of both the fungicides at 1000ppm concentration percent germination was found between 56 and 75 percent. Germination percent of spores was always lesser than control in all the treatments. Similarly germ tube growth was not occurred in copper oxychloride and mancozeb treated spores at 5000ppm concentration. Germ tube growth was found always influenced by the treatment of fungicides. Inhibitory effect of fungicides was dose dependent and proportional to the concentration of fungicides. Reduction in growth, spore germination and germ tube elongation increased on increasing the concentration of fungicides.