Microbes play an important role in organic farming, which is done without

the use of chemical fertilizers and pesticides. Bio-fertilizers are living

organisms which help increase the fertility of soil. It involves the selection

of beneficial micro-organisms that help in improving plant growth through

the supply of plant nutrients. Biofertilizers are introduced in seeds, roots, or

soil to mobilize the availability of nutrients. Thus, they are extremely

beneficial in enriching the soil with organic nutrients. Many species of

bacteria and cyanobacteria have the ability to fix free atmospheric nitrogen.

Rhizobium is a symbiotic bacteria found in the root nodules of leguminous

plants. Azospirillium and Azotobocter are free living nitrogen-fixing

bacteria, whereas Anabena, Nostoc and Oscillitoria are examples of

nitrogen-fixing cyanobacteria. Bio-fertilizers are cost effective and ecofriendly.

Microbes can also act as bio-pesticides to control insect pests in plants. An

example of bio-pesticides is Bacillus thuringiensis, which produces a toxin

that kills the insect pests. Dried bacterial spores are mixed in water and

sprayed in agricultural fields. When larvae of insects feed on crops, these

bacterial spores enter the gut of the larvae and release toxins, thereby it.

Similarly, Trichoderma are free living fungi. They live in the roots of higher

plants and protect them from various pathogens. Baculoviruses is another

bio-pesticide that is used as a biological control agent against insects and

other arthropods.