• Antagonists;
  • biological control;
  • glasshouse pathogens;
  • in vitro tests;
  • growth media


The growth of and interactions between the glasshouse pathogens, Rhizoctonia solani Kühn, Fusarium oxysporum Schlect., Pyrenochaeta lycopersici Schneider & Gerlach, Phomopsis sclerotioides van Kesteren, Sclerotinia sclerotiorum (Lib.) de Bary and Botrytis cinerea Pers. and the antagonistic fungi, Trichoderma harzianum Rifai, Trichoderma viride Pers., Coniothyrium minitans Campbell, Gliocladium roseum (Link.) Bain and Pythium oligandrum Dreschler were examined on tap water agar, soil extract agar and potato dextrose agar. The medium had a significant effect on the growth rates of the fungi as well as the production of, and response to, volatile and non-volatile antibiotic compounds and hyphal interactions. Responses to the media appeared to be related both to inherent properties of the fungi and to their natural ecological behaviour. The significance of in vitro assays in screening systems for biological control agents of soil-borne plant pathogens is discussed.