1. the artificial application of a natural control agent to regulate pest species —note the objective of biological control is to conserve or augment the natural or exotic enemy complex (predators, parasites, and disease) of the pest species by introducing pheromones, hormones, sterilization techniques, genetic manipulations, or plant resistance, as opposed to chemical control 2. interference in the pest's environmental status through management of the physical or biotic environment associated with the pest organism or population to reduce disease —synonym biocontrol, cultural control This definition last updated 10/24/2008