Mode of action of BCAs against RSB pathogen (R. solani): For example, Bacillus spp. are applied to rice for biological control of RSB where they act via a range of modes of action, but four modes of action are essential (a), Antibiosis by producing secondary metabolites such as antibiotics (b), Competition, i.e., competition for space and nutrients (c), Induce resistance in rice plants (d), They promote rice growth by secreting growth hormones.