ABSTRACT
The ecological conditions required for the development of various microbial pathogens – oomycetes, fungi, bacteria and viruses differ widely. Conditions favoring the development of the microbial plant pathogens, may result in epidemics, when susceptible cultivar is available in large areas. The susceptibility/resistance levels of the cultivars and the environmental conditions existing in the various agroecosystems are known to exert significant influence on both the pathogens and their host plants. The soil provides water and nutrients not only to the plants and microbial pathogens, but also to a wide range of organisms that interact with the plant hosts and the microbial pathogens.
