Alongside the use of disease-resistant cultivars, biological control is seen to have an important role in integrated pest management strategies aimed at reducing the use of chemical pesticides. A BCA is an organism or collection of organisms rather than a chemical per se. Biological control includes the use of predators, competitors, pathogens and compounds of biological origin. Microorganisms used include viruses, bacteria, fungi and protozoans. These may cause disease, or may compete with or otherwise limit the target organism. Biological controls tend to be highly specific. Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also involves an active human management role. Microbial biological control agents (MBCAs) are applied to crops for biological control of plant pathogens where they act via a range of modes of action. Some MBCAs interact with plants by inducing resistance or priming plants without any direct interaction with the targeted pathogen.

Microbial biological control agents (MBCAs) are applied to crops for biological control of plant pathogens where they act via a range of modes of action. Some MBCAs interact with plants by inducing resistance or priming plants without any direct interaction with the targeted pathogen. The mechanisms of action of microbial biocontrol agents against plant pathogens include direct antibiosis, hyperparasitism, induction of resistance and competition for space and nutrients. A wide variety of bacterial genera, including Agrobacterium, Alcaligenes, Arthrobacter, Bacillus, Enterobacter, Erwinia, Pseudomonas, Rhizobium, Serratia, Stenotrophomonas, Streptomyces, and Xanthomonashave been described to have plant disease protection activity against fungal and bacterial pathogens. There are three primary methods of using biological control in the field: conservation of existing natural enemies, introducing new natural enemies and establishing a permanent population and mass rearing and periodic release, either on a seasonal basis or inundatively. So, microbial agents are highly specific against target pests so they facilitate the survival of beneficial insects in treated crops. This may be the main reason that microbial insecticides are being developed as biological control agents during the last three decades. Biological control can generate multiple effects in food production, nutrient supply, and environmental health, thereby affecting economic development and ecological sustainability. Biological control is used primarily for controlling pests in crop cultivation. Advantages of biological control are that no artificial substances are added, and that pathogens / animals that develop resistance against biological control agents are rare

Biological control of plant diseases is important because it offers a sustainable and environmentally-friendly alternative to the use of chemical pesticides. The use of chemical pesticides can have negative impacts on the environment and human health, as well as lead to the development of pesticide-resistant strains of pathogens.

Microorganisms are commonly used as biological control agents against plant diseases due to their ability to colonize and compete with pathogenic organisms. Some microorganisms have the ability to directly inhibit the growth of pathogens through mechanisms such as antibiotic production, nutrient competition, and the secretion of lytic enzymes that degrade pathogen cell walls.

One group of microorganisms commonly used as biological control agents are bacteria, such as Bacillus and Pseudomonas species. These bacteria produce a range of antimicrobial compounds, including antibiotics and siderophores, which can inhibit the growth of plant pathogens.

Another group of microorganisms used as biological control agents are fungi, such as Trichoderma and Beauveria species. These fungi can produce hydrolytic enzymes that break down the cell walls of pathogens, as well as volatile organic compounds that inhibit the growth of pathogens.

In addition to bacteria and fungi, viruses and nematodes can also be used as biological control agents against plant diseases. For example, certain viruses can infect and kill specific plant pathogens, while nematodes can parasitize and feed on plant parasitic nematodes that cause damage to plants.

Overall, the use of microorganisms as biological control agents against plant diseases offers a sustainable and effective means of managing plant pathogens while minimizing the negative impacts associated with the use of chemical pesticides.

Dear Lalit Pandurang Patil thank you for your contribution to the discussion

The principal attributes of an effective biological control agent are: efficient searching ability, high parasitism or predation rate, high reproductive potential, minimal handling time, ability to survive at low prey densities and ability to adapt to a wide range of environmental conditions. Biological control can generate multiple effects in food production, nutrient supply, and environmental health, thereby affecting economic development and ecological sustainability. Biological control is used primarily for controlling pests in crop cultivation. Advantages of biological control are that no artificial substances are added, and that pathogens / animals that develop resistance against biological control agents are rare. Crop rotationis the oldest and best example of the known biological control methods, which is practiced by the farmers in India and other countries. On rotating a crop in a field, followed by other crop, alteration in gross microbial community in soil is done. By doing so, inoculums density of a pathogen is lowered. Biocontrol agents or microbial antagonists prevent infection of the host plant by the pathogen, or establishment of the pathogen in the host plant. The principal mechanisms for the control have been assumed to be those that act primarily upon the pathogens. Microbial biological control agents (MBCAs) are applied to crops for biological control of plant pathogens where they act via a range of modes of action. Some MBCAs interact with plants by inducing resistance or priming plants without any direct interaction with the targeted pathogen. A wide variety of bacterial genera, including Agrobacterium, Alcaligenes, Arthrobacter, Bacillus, Enterobacter, Erwinia, Pseudomonas, Rhizobium, Serratia, Stenotrophomonas, Streptomyces, and Xanthomonas have been described to have plant disease protection activity against fungal and bacterial pathogens. Microbes can arouse the process of germination and growth of plants, counteract common diseases and stimulate resistance to stress and overall physical vigor and robustness, improve nutrient utilization efficiency, as well as prevent diseases and provide tolerance against abiotic stresses. These microbes include bacteria, fungi, viruses, and protozoans. Microbes act as biocontrol agents in three ways, either they cause diseases in the pests or compete with them or kill them.