Spiders, for example, feed on many different hosts including other natural enemies. The natural enemy must be effective at searching for its host and it should be searching for only one or a few host species. A successful natural enemy should have a high reproductive rate, good searching ability, host specificity, be adaptable to different environmental conditions, and be synchronized with its host (pest).ДЄ high reproductive rate is important so that populations of the natural enemy can rapidly increase when hosts are available. This guide concentrates on those species for which the benefits of their presence outweigh any disadvantages. In potatoes grown in Maine, 22 parasitoids of aphids were identified, yet these were attacked by 18 additional species of hyperparasitoids. For example, hyperparasitoids are parasitoids of other parasitoids. The behaviors and life cycles of natural enemies can be relatively simple or extraordinarily complex, and not all natural enemies of insects are beneficial to crop production. Each of these natural enemy groups is discussed in much greater detail in following sections.

They kill or debilitate their host and are relatively specific to certain insect groups. Pathogens are disease-causing organisms including bacteria, fungi, and viruses. Many species of wasps and some flies are parasitoids. Parasitoids are species whose immature stage develops on or within a single insect host, ultimately killing the host. Predators, such as lady beetles and lacewings, are mainly free-living species that consume a large number of prey during their lifetime. Biological control agents of plant diseases are most often referred to as antagonists. Biological control of weeds includes insects and pathogens. Natural enemies of insect pests, also known as biological control agents, include predators, parasitoids, and pathogens. This guide emphasizes the biological control of insects but biological control of weeds and plant diseases is also included. This is frequently referred to as natural control. Keep in mind that all insect species are also suppressed by naturally occurring organisms and environmental factors, with no human input. It is defined as the reduction of pest populations by natural enemies and typically involves an active human role. Purchase and Release of Natural EnemiesД«iological control is a component of an integrated pest management strategy.This segment includes several paragraphs with general information about biological control and these subsections:

Microbes as biocontrol agents pdf notes