Book excerpt: Biological disease management tactics have emerged as potential alternative to chemical application for containing crop diseases. Biotic and abiotic biological control agents (BCAs) have been demonstrated to be effective against diseases caused by microbial plant pathogens. Combination of biotic and abiotic agents leads to synergism and consequent improvement in the effectiveness of disease control. It is essential to assay the biocontrol potential of all isolates/species of fungal, bacterial and viral biocontrol agents by different techniques in vitro and under greenhouse and field conditions and to precisely identify and differentiate the most effective isolates from less effective ones by employing biological, immunological and nucleic acid-based assays.