Biological control may be defined as the use of natural enemies to limit pest species. The term natural enemy refers principally to parasites and predators (mostly other insects) but may also include disease microorganisms. In Russia and China
farm managers have used a parasite that eats insect eggs (a tiny parasitic wasp called Trichogramma) as a way to reduce insect populations. In fruit orchards predatory mites and insects can provide effective control of the harmful fruit tree red spider mite. An example of a disease microorganism used to cause disease in insects is ‘ Verticillium lencanii ’, which is a pathogenic fungus that kills aphids and whitefly; however, it is effective only in greenhouses.