Biological control of the soil-borne fungal pathogen Sclerotinia sclerotiorum - a review

Diseases caused by Sclerotinia sclerotiorum (Lib) de Bary are difficult to control and cause increasing losses of horticultural crops worldwide. Reasons of this phenomenon are various: (i) the specialization of crop production that causes the accumulation of the pathogen in the soil; (ii) the lack of a safe and efficient method of soil fumigation; (iii) the specific life cycle of S. sclerotiorum with survival structures (sclerotia), resistant to chemical and biological degradation. Sclerotinia diseases depend on many environmental factors which determine sclerotia survival and ascospores dissemination, because plants are mainly infected by air-borne ascospores from carpogenic germination of sclerotia. Due to the lack of effective synthetic agents for eradication of S. sclerortiorum from soil considerable interest has been focused on biological control, especially the selection of microorganisms with mycoparasitic activity towards S. sclerotiorum sclerotia, that can decrease their number in the soil. In this work we review reports on the use of different antagonistic fungi and bacteria in the control of S. sclerotiorum and discuss the suppressive effect of organic amendments against this soil-borne pathogen.