Biological control is an important component of any integrated pest management (IPM) program. Most pests have natural enemies that regulate their population. These natural enemies (or biological control agents) have evolved over time to be highly adapted to searching out and feeding on their host.
Insect biological control agents are usually described as predators or parasites.
Cryptolaemus is a powerful predator Dan Papacek
Predatory insects include ladybird beetles, lacewings and preying mantids. They feed on prey to complete their development. Often predatory insects will feed on a range of life stages of a particular pest (eg eggs, larval and adult stages).
Aphytis - a parasite of red scale Denis Crawford
Insect parasites are more correctly termed parasitoids. Examples include tiny wasps such as aphytis and trichogramma as well as some flies. They can be very powerful biological control agents and work in quite a different way to predators. Insect parasites lay their egg (or eggs) into or on a specific life stage of the pest that they are adapted to feed upon. When the egg hatches it starts to devour the host and will complete its development entirely on that host.
Types of biological control
Biological control is often divided into three categories. All of these can be part of an integrated pest management program.
The three categories are:
- Classical biological control
- Augmentative biological control
- Conservation biological control