Role of biological agent in plant diseases management

Plant diseases damage to agricultural crops in every year. Different approaches may be used to prevent the growth and reduce damage of plant diseases gents. Including methods is using of biological control. That is an environmentally sound and effective means of reducing plant diseases effects. Actually, the rhizosphere supports the development and activity of a huge and diversified microbial community, including microorganisms capable to promote plant growth, which could be used by these organisms for biological control of plant pathogens. Among the plant growth-promoting factors can be named as Trichoderma sp. fungus and strains of Bacillus sp. and Pseudomonas sp. had widely used in biological control of plant diseases. These biological agents make use of different mechanisms to control plant diseases, such as activate defense responses, antibiosis, stimulate plant growth, antibiotics production, increase nutrient uptake, siderophore and HCN production. Therefore, propagation and inoculation of these biological agent to plants, can decrease usage of chemical fertilizers and pesticides. Integrating mechanistic and ecological knowledge on these microorganism populations in soil will be a prerequisite to develop novel management strategies for sustainable agriculture