Biological Control

Managing the health and beauty of trees, shrubs and flowers with minimal pesticide use is often called integrated pest management or IPM. It involves looking at the total landscape; identifying the particular pests or growing conditions that appear to be causing a problem; and if any action needs to be taken, choosing from a variety of sound management strategies. These strategies include cultural practices and several types of Acontrol including biological, genetic, mechanical or physical, regulatory, and chemical. IPM has been called the common sense approach to controlling pests.

Insect pests frequently have natural enemies that help us keep them under control so that other types of control, such as pesticides, are not needed. These insects and spiders, referred to as beneficials, often exist in the landscape naturally but they also can be introduced. Beneficials may be predators or parasites. One common example of a beneficial predator is the lady beetle. Both the larvae and adult lady beetles eat aphids and other soft-bodied insects. Other important predators include lacewings, spined soldier bugs, flower flies and spiders. Parasites are organisms that live on or inside another organism called the host. The host often dies after the parasite has completed its development. Most typical parasites are small wasps flies that use caterpillars, whitefiles, aphids and and other pests as hosts. Some of our introduced pests, such as the Japanese beetle, have had natural enemies introduced from their original homelands in efforts to provide biological control. This is because natural enemies for introduced pests often do not exist here.

Another type of biological control, sometimes called microbial control, is the use of disease-causing bacteria, viruses, fungi, or nematodes as control agents. A good example of this type of control is the use of the bacterium, Bacillus thuringienses or Bt, to control pests. Bt produces a toxin that is specific towards certain types of pests, such as caterpillars. The Bt toxin can be sprayed on plant foliage and when eaten by caterpillar pests, causes them to die in a few days. One of the strong points of this type of biological control is that it is specific towards certain types of pests and will not harm other insects in the landscape, such as ladybeetles.