Abstract: Actinomycetes enhance soil fertility and have antagonistic activity against wide range of plant root-pathogens. These micro organisms were isolated from agricultural soils of Kerman and Fars Provinces as pure cultures. Pythium aphanidermatum, causes damping off and root and stem rots of cucurbits worldwide. From 178 Actinomycetes isolates, 43 inhibited growth of the pathogen in culture plates and two of the most active isolates exhibited biological control of the pathogen under greenhouse conditions. When plants were grown in sterile soil mix and treated both with Actinomycetes and the pathogen, the number of healthy plants increased dramatically and the symptoms on diseased plants were less severe in comparison with seedlings treated with the pathogen alone. From the collected data it was well conclusive that in greenhouse tests, soil applications of Actinomycetes controlled causal agent of damping off in cucurbit seedlings. Antifungal activity was of fungicidal type on the pathogen mycelia. Regarding biotechnological implications, the results indicate that the active isolates can be investigated for use as biofertilizers, biofungicides and use in future development of recombinant DNA in cucurbits bearing elevated resistance to damping off. Field trials of the active isolates are under investigation.
F. Sharifi , P. Rashid Farrokhi , G.H. Shahidi Bonjar , S. Aghighi , F. Aram and E. Khalesi , 2007. Biological Control of Pythium aphanidermatum, the Causal Agent of Damping off Disease of Greenhouse Cucurbits in Kerman Province of Iran. Research Journal of Biological Sciences, 2: 188-191. Asian Journal of Information Technology, 18: 250-260.