ABSTRACT
Despite these promising results and several years of research, the number of products in the market is still very limited (Mathre et al., 1999). Most products have been elaborated for soil application to control soil-borne plant pathogens. The first biological control product with authorization for the German market is for this use. The product, Contans WG15, is based on the parasitic fungus Coniothyrium minitans, which attacks and destroys the sclerotia of Sclerotinia
conditions are more stable and factors having an influence on biological control agents are limited (Andrews, 1992). In soil, the amplitude of temperature and humidity is less pronounced as compared to the aerial environment. Despite these advantages of soil, establishing an antagonist in this habitat is challenging, since antagonists are subject to numerous competition mechanisms. In this situation, the antagonist is an immigrant competing against established inhabitants. Only if the antagonist is able to establish in this new habitat, can sufficient effectiveness be achieved, because it depends in most cases on population density (Andrews, 1992). Apart from application to soil, the other forms of biological control relate to management of postharvest diseases (Wilson and Pusey, 1985; Janisiewicz and Korsten, 2002; Shi-Ping Tian, Chapter 6 in this volume).
