Often, natural enemies are in the range of the invading pest. Notable examples of classical biological control include the use of decapitator flies (several species of Pseudacteon) against imported red ants, and a group of beetles, fleas, thrips, and stem borers used against alligators. Biological control, the use of living organisms to control pests. A natural enemy, such as a parasite, predator, or diseased organism, is introduced into a pest's environment or, if already present, encouraged to multiply and be more effective in reducing the number of pest organisms.
Examples of biological control include destruction of cochineal citrophilus in California by two parasitic species of calcid wasps imported from Australia, Coccophagus gurneyi and Tetracnemus pretiosus; effective predation of an Australian ladybug or vedalia beetle (Rodolia cardinalis), on the cushion scale California cotton; limiting European rabbit proliferation in Australia by introducing myxoma virus (which causes myxomatosis disease); control of Japanese beetles by Bacillus popilliae, which causes milky disease; and control of several larvae that attack food crops in home gardens caused by Bacillus thuringiensis, a bacterium that lives in the soil. In China, agricultural production and pest management systems take advantage of low labor costs and, in general, follow highly innovative but technologically simple processes. They are released by flooding to suppress the sugar cane borer, Chilo spp. Parasitized eggs raised by insects are wrapped in sections of leaves, which are then slipped by hand over sugarcane leaves.
Most Trichogramma production in China is carried out in facilities that produce material for a localized area. These facilities range from outdoor insectariums to mechanized facilities that lead the world in the development of artificial host eggs. Biological pest control involves the use of other organisms, these can be microbes, parasites, predatory insects and even small animals, such as birds. As a result, biological control continues to provide productive, efficient and cost-effective solutions to pest problems.
This is the practice of importing, and releasing for establishment, natural enemies to control an introduced (exotic) pest, although it is also practiced against native insect pests. Hundreds of biological control products are commercially available for dozens of invertebrate, vertebrate, weed and plant pathogen pests (Anonymous 199). Biological control is the study of the relationships between weeds, their associated organisms and the environment, followed by the manipulation of species of these organisms (natural enemies) to the detriment of a target weed species. Some of these researchers believe that biological control is fundamental to IPM, but funding for biological control research is less than 20% of the total given to IPM.
A small wasp, Trichogramma ostriniae, introduced from China to help control the European corn borer, is a recent example of a long history of classic biological control efforts for this large pest. New biological control efforts are now needed for many existing pest problems, both for programs directed against introduced pests and for additional work towards conserving the natural enemy in pest management systems. Related to biological pest control is the technique of introducing sterile individuals into the native population of an organism. In many cases, if not in most cases, biological control alone does not provide economically acceptable pest suppression in agricultural cropping systems.
Over the past quarter-century, research and implementation of biological control for fruit pests of deciduous trees has tended to emphasize the increase and conservation of natural enemies associated with secondary indirect pests of these crops, such as mites, aphids, leaf miners, scales and leafhoppers. Control is greater if the agent has temporary persistence so that it can maintain its population even in the temporary absence of the target species, and if it is an opportunistic forager, allowing it to quickly exploit a pest population. In the future, a balance must be sought between research and conservation and the increase of native natural enemies compared to classic studies of biological control of pests imported from these crops. Many of these introductions do not result in the establishment or, if they do, the organism may not become a pest.
However, costs fall to low or even zero levels in recent years, while the benefits of achieved pest control continue to accumulate for years. In Phase III, the loss of biological control activity occurs when organic matter begins to wet and the availability of organic nutrients from the soil to biological control agents becomes limiting. . .
