This involves the use of natural enemies (bred specificly for this purpose) to fight pests and diseases. The natural enemies do this as follows:

• They suck the plague organism empty , such as the larva of the lacewing and the gall midge and the predatory mite
• They lay an egg in the plague organism, such as the parasitic wasp.
• They eat the pest organism, such as the larvae of the ladybug and the predatory bug
• They secrete toxic compounds into the plague or pest organism to make it ill in one or another way, such as nematodes and bacteria

External links

• http://en.wikipedia.org/wiki/Biological_pest_control

Literature

• Plant-provided Food for Carnivorous Insects: A Protective Mutualism and its Applications by Felix L. Wäckers
• Manage Insects on Your Farm: A Guide to Ecological Strategies - Freely downloadable book (PDF-file)