Augmentative biological control: The release of additional numbers of a natural enemy when too few are present to control a pest effectively. This relies on an ability to mass-produce large numbers of the natural enemy in a laboratory. For instance, there are native species of predatory mites which attack and kill pest mites on strawberries and other crops. Growers can buy large numbers of these predatory mites to augment those already on their crops, and so achieve biological control of the pest mites.