Bio control refers to the use of biological methods for controlling plant diseases and pests. Excessive usage of insecticides and pesticides leads toxicity to humans and animals alike and also pollute the environment. Our soil is also polluted due to the use of weedicides. If we use chemicals on diseased plants, both beneficial predatory and harmful insects will die. Thus the use of bio-control agents will greatly reduce our dependence on toxic chemicals and pesticides.

(1) The very familiar beetle with red and black markings - lady bird, and dragon flies are useful to get rid of aphlids and mosquitoes. 

(2) Microbial bio-control agent to control butterfly caterpillar is Bacillus thuringiensis. These are available in sachets as dried spores which are mixed with water and are sprayed onto vulnerable plants such as brassicas and fruit trees, they are eaten by the insect larvae. The toxin is released in the gut of the larvae, and the larvae gets killed. The bacterial disease will kill the caterpillars but leave other insects unharmed. Through Genetic Engineering method, scientists have introduced Bacillus thuringiensis toxin genes into plants. Such plants are resistant to attack by insect pests. 

Ex : Bt-Cotton, Bt-Brinjal.

(3) Trichoderma species are free living fungi that are very common in the root Ecosystems. They are effective Bio-control agents of several plant pathogens.

(4) Baculoviruses Baculoviruses are pathogens that attack insects and other arthropods. They are in the genus, Nucleo Polyhedro virus. These viruses are excellent candidates for species specific, narrow spectrum insecticidal applications.