Mechanisms of Biological Control of Plant Pathogens and Plant Parasitic Nematodes

Plant disease prevention/control by using chemical fungicides was the most widely used method but the high cost of chemical fungicides; their consequences on bio safety and also development of resistance in target organisms lead many researchers to apply the concept of organic farming using the activity of micro organisms (bio control agents) to replace the chemical pesticides. The mechanisms by which the bio control agents known to act on plant pathogens include, competition, antibiosis, hyper parasitism, predation, by inducing systemic resistance and by promoting plant growth. Biological agents act on plant pathogens without affecting the bio safety and ecological balance at affordable cost. Thus, there is a growing demand for sound, biologically-based pest management practices. Recent surveys of both conventional and organic growers indicate an increasing interest in using bio control products, suggesting that the market potential of bio control products will increase in coming years. Total revenues of products used for bio control of plant diseases represented just a small fraction of the total pesticide market during the first few years of the 21st century indicating the replacement of chemical pesticides by bio control agents.