Synergizing biological control: Scope for sterile insect technique, induced plant defences and cultural techniques to enhance natural enemy impact

When used alone, only a minority of biological control programs succeed in bringing the target pest population under sufficient control. Biological control is, therefore, usually employed with chemical, cultural, genetic or other methods in an integrated pest management (IPM) strategy. The interactions between different pest management methods, especially conventional pesticides and host plant resistance, is an area of growing research interest but relatively little consideration is given to novel combinations. This paper reviews the interactions between biological control and other forms of pest management, especially induced plant defences and the novel, non-toxic plant protection compounds that may boost these defences; and sterile insect technique. We also cover the cultural methods that offer scope to support synergies between the aforementioned methodological combinations. We conclude that despite the sometimes negative consequences of other pest management techniques for biological control efficacy, there is great scope for new strategies to be developed that exploit synergies between biological control and various other techniques. Ultimately, however, we propose that future use of biological control will involve integration at a greater conceptual scale such that this important form of pest management is promoted as one of a suite of ecosystem services that can be engineered into farming systems and wider landscapes.