Abstract

This study was carried out to evaluate the efficiency of Saccharomyces cerevisiae; Kluyveromyces marxianus; Pseudomonas fluorescens; Bacillus subtilis and Biokont against Phytophthora nicotianae the causal agent of okra damping off. The pathogenic fungus was isolated from infected seedling and identified on the basis of cultural and molecular characteristics. The pathogenecity of the isolate was determined on okra seedling. The antagonistic activity of biocontrol agents against P. nicotianae was tested on cultural medium by dual culture test. The more effective concentration of biocontrol agents was determine by mixing different concentrations from those agents with cultural medium and inoculated the medium with the pathogenic fungus. The efficiency of biocontrol agents in controlling seedling death was evaluated by adding the effective concentration of the agent into poting soil, then contaminated with the pathogenic fungus and sown with okra seeds. The results showed that all the biocontrol agents inhibited the fungal growth on cultural medium by 69; 65; 67 and 59% for each of S. cerevisiae; K. marxianus; P. fluorescens and B. subtilis respectively. The inhibition percentage was found to be 100% when the biocontrol agents were mixed with the medium at 7 x 105; 3 x 106 and 7 x 106 colony forming units/ml for K. marxianus ; P. fluorescens and B. subtilis and at 0.1; 0.3; 0.5 g/L of S. cerevisiae powder. All the biocontrol agents have reduced seedling death 0.0; 0.0; 0.0; 6.7; 6.7; 6.7; 6.7; 13.3% with Biokont; S. cerevisiae; K. marxianus and P. fluorescens before and after emergence respectively compared with 33.3 and 40% in control, while the seedling death attained to 13.3 and 20% in soil treated with B. subtilis before and after emergence respectively.

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The article was added to IASJ on 2013-03-31

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