Natural enemies plays a important role in the management of harmful insects, diseases and weeds in protected as well as open field conditions. Four main categories of natural enemies are predators, parasites, parasitoids and pathogens. Now a days, many farmers using synthetic pesticides to eradicate the harmful insects. This practice may also affects the natural enemies and the bionomics of the pollinators. The main objective of this article to know the diversity of natural enemies and their conservations strategies followed by the farmers so that the farmers can get rid out of the harmful insects at low cost and to minimize the adverse effect of the pesticides on the environment or agro-ecosystem. To avoid these harmful effects, farmers should use bio-pesticides, which do not cause any side effects on the biocontrol agents present in the environment, as well as to reduce the pest outbreak.