Suppression of Damping-off on Pepper Caused by Pythium ultimum Trow and Rhizoctonia solani Kühn by Some New Antagonists in Comparison with Trichoderma harzianum Rifai.

Pot experiments were designed to evaluate the efficacy of Streptomyces nobilis, S. ochraceiscleroticus, Neocosmophora vasinfecta var. africana and Acrophialophora levis isolates in reducing the damping-oil on pepper in comparison with a strong mycoparasitic isolate of Trichoderma harzianum. Two pathogenic and five potential antagonistic isolates were grown separately in flasks containing a mixture of sand-perlite-corn meal and potato-sucrose broth for 4 weeks. Soil infestation was achieved by mixing these stock cultures separately into the pot soils. Disease incidence vas expressed as the percentages of dead seedlings in each pot and the protective values of the antagonists were calculated according to Abbott formula. Results indicated that all of the five test isolates have provided the seedlings with protection of statistical value against Pythium ultimum and Rhizoctonia solani reducing disease incidence between 28.14 to 79.14% and 22.76 to 66.83%, respectively. However, T. harzianum isolate proved to be the least effective antagonist against both pathogens. [ABSTRACT FROM AUTHOR]