Predators are generally as large, or larger than the prey they feed on. They are quite capable of moving around to search out their food, and they usually consume many pest insects during their lifetime. Ladybird beetles, lacewings , and syrphids are examples of insect predators. Parasitoids, or parasitic insects, are smaller than their prey. One or more parasitoids grow and develop in or on a single host.
Most parasitic insects are wasps or flies.
Adult parasitoids do not usually feed on insects, but are highly mobile, laying eggs in many hosts. Aphids, leafminers, leafrollers and other caterpillars are often attacked by parasitic insects. Beneficial insects and mites can help prevent or delay the development of pesticide resistance in orchards by reducing the number of pesticides required to control a pest. They will also feed on the resistant pests that survive a pesticide application. When chemical controls are necessary in an IPM program, pesticides recommended are those that have minimal impact on beneficials naturally occurring in the orchard.