The bio-agents such as Bacteria- (Bacillus thuringiensis), Fungi (Beauveria, Metarhizium, Verticillium, Nevorium), Virus (NPV), etc are widely used for control of various pests in agriculture. These bioagents will produce non-toxic biological material (protein) which is harmful to pests. The use of biological control suppresses the pest populations, making them less damaging than they would be. They play an important role in limiting the densities of potential pest and include natural enemies such as predators, parasitoids, and pathogens. Preventive measures and biological control methods should be preferred for protecting crops because these methods are ecologically safe and these methods do not harm various life forms. The high use of chemicals causes many environmental problems and leads to pollution.

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. 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. Biological control is particularly desirable because the tactic is environmentally safe, energy self-sufficient, cost-effective, sustainable, and can be readily incorporated into integrated pest management) programs. Furthermore, in many cases benefits from the use of natural enemies accrue at no additional cost. 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. The most commonly used biopesticides are living organisms, which are pathogenic for the pest of interest. These include biofungicides, bioherbicides and bioinsecticides. Microbes act as biocontrol agents in three ways, either they cause diseases in the pests or compete with them or kill them. Microbial control of insects is the concerted use of insect-specific pathogens and nematodes for the biological control of insects. Microbial pesticides have a number of advantages over conventional chemical pesticides.