Biological control is the use of a specially chosen living organism to control a specific pest.
This chosen organism might be a predator, parasite, or disease that will attack a harmful insect or weed. Biological control is a form of manipulating nature to achieve a desired effect. Biological control methods can be used as part of a broad-based program to reduce the environmental, legal, and health hazards of chemicals in the garden. In addition, biological control may be a less expensive alternative to certain insecticides. Some biological control measures can actually prevent economic damage to plants.