Abstract: This invention refers to the pure culture of a wild isolate of the fungal species Fusarium solani (code name: strain ‘Fs-K’) and to its use for the biological control of plant pathogens. The invention includes the mycelium of the strain ‘Fs-K’ and any genetic modification of it, the asexually produced conidia and chlamydospores of the strain ‘Fs-K’, and the cultures of the strain ‘Fs-K’ (grown on liquid or solid media) which contain the mycelium and/or the conidia and/or the chlamydospores, as well as any extract or ingredient which derives from the growth of the strain ‘Fs-K’ or from the growth of any genetic modification of it. The invention further includes organic substrates for plant growth, as well as any other substrate compositions suitable for the growth of fungi and/or plants which contain forms of the strain ‘Fs-K’ (i.e. any vegetative or reproductive structure of it which is involved in the biological control of diseases).