Biological Control of pests requires active human role. Here reduction of pest population is made effective by natural enemies. These natural enemies of insect pests are called biological control agents. They include predators, parasitoids and pathogens.
Predators are such species which consume a large number of preys during their life span that are lady beetles and lace wings. Parasitoids finally kill the host. Their immature stage developments on or within that single host and most have a very narrow host range for example wasps and flies. Pathogens are organisms which cause diseases for example bacteria, fungi, viruses. They also kill the host.
Biological control strategies are basically of three types- Conservation, Classical Biological Control and Augmentation.
Home owners and gardeners find conservation of natural enemies very easy. It is the most available available method to control pests these days. They are present everywhere and are adapted to local environment. As such their preservation is very easy. Since biological controls are also harmed by the same pesticides used to target their hosts, prevention of such accidents should be taken care of. Such prevention is called simple conservation.
Classical Biological Control is usually done by government authorities. It is done by introducing natural enemies to a new locality where they do not belong or occur naturally. This process is inexpensive and long lasting.
Augmentation involves the controlled release of natural enemies. Relatively less natural enemies will be released at a critical season or millions of them will be released as per the need.
You should do a lot of research before using any type of pest control methods. Every method has it`s own advantages and disadvantages. The method should be selected according to the needs of the household. It is a good idea to spend some time online before you take a new step.