Introduction and augmentation of biological control agents

Natural enemies play key roles in pest management programs worldwide. Using natural enemies in pest management requires an understanding of their basic biology, how they impact pest population growth and how the environment and management system affect natural enemy dynamics and performance. Whereas there are abundant examples of using natural enemies in weed and plant pathogenic systems (VanDriesche & Bellows, 1996; Coombs et al., 2004), in this chapter we focus on insect pests and their associated predatory, parasitic and pathogenic natural enemies. Although natural enemies that occur naturally in crops can provide substantial control and are the cornerstone of many pest management programs, we will focus on approaches that intentionally add natural enemies to affect pest control. Examples of manipulating the environment to increase the number or effectiveness of natural enemies, sometimes referred to as conservation biological control, are given in several chapters in the current volume or in VanDriesche & Bellows (1996), Barbosa (1998) and Bellows & Fisher (1999). In this chapter we review approaches to introduce or augment natural enemies, provide case histories to illustrate their use and suggest research needs to increase the use of biological control agents in pest management. General texts on biological control (e.g. Debach & Rosen, 1991; VanDriesche & Bellows, 1996; Bellows & Fisher, 1999) provide a broader overview of the methods and use of biological control in pest management systems.