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Organic Farming

Organic Methods Of Managing Pests

In agriculture, pests are any organisms that significantly interfere with the productivity of crop plants or animals. This can occur when insects eat foliage or stored produce, when bacteria or fungi cause plant or animal diseases, or when weeds interfere excessively with the growth of crop plants. In conventional agriculture, these negative influences of pests are usually managed using various types of pesticides, such as insecticides, herbicides, and fungicides. On the shorter term, these methods can be effective in reducing the influence of pests on agricultural productivity. However, important environmental damages can be associated with the use of pesticides.

Organic farmers do not use synthetic, manufactured pesticides to manage their pest problems. Rather, reliance Comparison of organic and conventional farming methods. Illustration by Hans & Cassidy. Courtesy of Gale Group.
liance is placed on other methods of pest management, the most important of which are:

  1. The use of varieties of crop species that are resistant to pests and diseases. If the crop species has genetically based variations of tolerance to the pest or disease, then resistant varieties can be developed using standard breeding techniques;
  2. Attacking the pest biologically, by introducing or enhancing populations of its natural predators, parasites, or diseases;
  3. Changing other ecological conditions to make the habitat less suitable for the pest. Depending on the pest, this may be possible by growing plants in mixed culture rather than in monoculture; by rotating crops or by using a fallow period so that pest populations do not build up in particular fields; by managing the overwintering microhabitat of certain pests; by using mechanical methods of weed control such as hand-pulling or shallow plowing; and by other means. Obviously, use of these techniques requires knowledge of the ecological requirements and vulnerabilities of important pest species.
  4. Undertaking careful monitoring of the abundance of pests, so that specific control strategies are used only when required. Note that this may include the use of certain pesticides, but these must be based on a natural product. For example, an insecticide based on the bacterium Bacillus thuringiensis (or B.t.) may be acceptable, as may one based on pyrethrum, a chemical extracted from several species of plants related to the daisy. However, synthetic analogues of these, such as genetically engineered B.t. or synthesized pyrethroids are not considered acceptable in organic agriculture.

Note that many of these pest-control practices are important components of a system known as integrated pest management. However, in that system pesticides are often used as a last resort, when other methods do not work effectively enough. In organic agriculture, pesticides are not used (other than the "natural" ones just referred to).

In addition, organic farmers, and the consumers of the goods that they produce, must be relatively tolerant of some of the damages and lower yields that pests cause. Consumers, for example, may have to be satisfied with apples that have some degree of blemishing associated with scab, a fungal-caused problem that does not affect the nutritional quality or safety of the apple, but has become associated with poor aesthetics. In conventional agriculture, this cosmetic damage is managed through the use of pesticides, in order to supply consumers with apples of an aesthetic quality that they have become conditioned to expect.


Additional topics

Science EncyclopediaScience & Philosophy: Octadecanoate to OvenbirdsOrganic Farming - Organic Methods Of Maintaining Soil Tilth And Fertility, Organic Methods Of Managing Pests, Use Of Antibiotics And Growth Regulating Hormones