eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2018-06-25 15 2 439 446 10.13005/bbra/2648 30177 article Mitra Abootorabi 1 Microbial Biotechnology, Tehran-Shomal Branch, Islamic Azad University, Tehran, Iran. The excessive use of chemical pesticides to confront pests causes environmental pollution. Furthermore, plant pathogens resist chemical pesticides. When such pathogens accumulate in plants or soil, they will cause harmful effects on humans. Biological control is an alternative method that reduces or terminates the use of chemical compounds in agriculture. Biological control is also carried out by microorganisms. Bacteria are the main group of these microorganisms. Due to the extensive presence in the soil, tolerating changes of temperature, pH, and salinity as well as producing endospore resistant species, Bacillus bacteria are used in biological control of soil. Bacillus species are often found in soil and rhizosphere. These bacteria help with the control of plant pathogens by producing siderophore, secretion of enzymes, production of antibiotics and inducing systemic resistance. In this study, various biological control mechanisms which are carried out by microorganisms have been reviewed. https://www.biotech-asia.org/vol15no2/a-review-on-the-biological-resistance-of-terricolous-microorganisms/ Bacillus; Flavius; Fumigatus; Metabolite; Niger; Standard Aspergillus Fungi