Abiotic Biological Control Agents for Crop Disease Management

Abstract

Biological management of crop diseases can be achieved to the desired level by judiciously integrating the biotic and abiotic agents with different mechanisms of action on the target pathogen(s). A wide range of sources of abiotic agents has provided the materials for enhancing the activities of biotic biocontrol agents, resulting in effective disease suppression. Addition of organic amendments such as composts and green manures is known to increase the population and activities of microbial communities that positively influence plant growth and protection offered to plants against microbial plant pathogens. The biosurfactant function of brassica crop amendments has been demonstrated to reduce the incidence and severity of soilborne diseases. Plant extracts and secondary metabolites of plants, like essential oils are effective in reducing pathogen population and disease incidence of soilborne and foliar diseases. Fumigation with thymol has the potential for use as an alternative to chemicals used for the management of postharvest diseases. Naturally-derived compounds like chitosan have high level of biocontrol potential, primarily by enhancing resistance of plants and harvested produce against microbial pathogens. Plant activators such as salicylic acid and acibenzolar-S-methyl (ASM) have been demonstrated to possess marked potential for protecting plants against a wide range of microbial plant pathogens. Phosphates are inexpensive inorganic chemicals that may increase the level of resistance in treated plants to diseases. Likewise, silicon is another inorganic source of resistance inducers, deserving wider exploitation for disease management. Abiotic biocontrol agents are available in large numbers, awaiting recognition by discerning discoverers for realizing their potential.