Ada — Most people think only of pests when they think of insects. In fact, most insects found in yards, gardens or crops do not feed on or harm plants. Many of these are just “passing through” or have very innocuous habits.
Others feed on and destroy pest species. In many cases, the activities of these beneficial species can prevent or greatly limit pest problems. It is important to recognize these beneficial insects so they can be appreciated and conserved.
Beneficial insects can be categorized broadly as either predators or parasites.
During development, in both adult and immature stages, insect predators actively search out and consume several prey insects. Predators include lady beetles, green lacewings and damsel bugs.
Insect parasites develop in or on a single host from eggs or larvae deposited by the adult parasite. Common parasites include tachinid flies and many kinds of wasps.
Use of beneficial insects
in pest control
Over the past few years, there has been a tremendous interest on the part of the general public to reduce the use of pesticides in and around the home and, at the same time, an increased interest in the use of natural enemies to control insect pests.
Individuals should keep in mind that the use of natural enemies against insect pests (biological control) is nothing new and has been studied by entomologists for more than 75 years.
Biological control of pests appears to be feasible in greenhouses. Various experiments have shown good control of spider mites, whiteflies, mealybugs and aphids through releases of a variety of predacious mites, parasitic wasps and lady beetles.
Experiments out-of-doors have not enjoyed the successes of those in greenhouses. One situation in which releases show considerable promise is in using parasitic wasps to control house flies and other filth-breeding flies around livestock operations. Several species of wasps have been tested, most commonly in caged poultry houses.