Biological control.

This chapter focuses on attempts to control aphids using (1) classical biological control involving introductions of natural enemies into geographical areas where they did not previously occur and usually directed against introduced pests, and (2) augmentation involving mass rearing and release of natural enemies that already exist in the system but which do not occur naturally in sufficient numbers, or at the optimum time to control the target pest. The use of parasitoids, predators and entomogenous fungi against aphids are described.