The Antagonistic Activity of Actinomycetes of Streptomyces Genus in Relation to Trichoderma Koningii

The aim of the study was to estimate the effect of actinomycetes of genus Streptomyces on the growth of the antagonistic fungus Trichoderma koningii. 150 strains of Streptomyces spp. isolated from two potato cropping systems were used to the tests. Analyses were conducted experimentally in vitro on PDA medium with pH 6 and 7. The results obtained clearly indicate the inhibitory effect of actinomycetes on the fungus T. koningii. Of the tested population of actinomycetes only two strains did not inhibit the growth of the tested fungus. The strains from the rhizosphere of potato cultivated under the ecological system were predominant in the group of actinomycetes with a very strong effect. pH value appeared to be a crucial factor influencing the inhibition zone. High antagonistic activity in relation to the useful fungus T. koningii noted with numerous strains of Streptomyces spp. is unfavorable in respect of biological control.