Biological control

Agricultural production relies not only on crops but on associated biodiversity in agro-ecosystems. Pests, diseases and weeds limit crop production, and are themselves limited by the action of their natural enemies, mostly arthropods and micro-organisms. Biological control, through an ecosystem approach, is a way to reduce pesticide use and enhance biodiversity while ensuring production.

Animal diseases cause heavy economic losses both for individual farmers and at national or regional levels. Gastro-intestinal nematode parasitism is one of the most important disease constraints to small ruminant production in the sub-tropics and tropics. It is possible to biologically control of gastro-intestinal nematodes of ruminants using predacious fungi. Also, poultry are used for controlling ticks and other vectors of animal and human disease.

Fish populations serve as regulator of food webs and can influence community structure of other species and thereby also regulate pests and diseases. Grass carp (white amur), for example, were introduced to the United States in 1963 for aquatic weed control. However, unintended consequences may occur so, when using biological control, either enhancing an existing population or bringing a new population, it is key to well understand the ecosystem interactions to avoid promoting a species over another and changing the ecosystem balance. Sustainable fisheries and stock management can support balancing different populations and making the best use of biological control.

In forest, when needed, the biological control of pest is often the chosen methodology since the relatively stable environment of a forest guarantees freedom from such adverse effects as interference by pesticides or disturbing agricultural practices. Natural or sustainably managed forests are also great reservoir of natural pest eradicators.