A microbial-based pesticide is a type of pesticide that is made with microorganisms or their by-products. Microbial-based pesticides are seen by some people as preferable to pesticides with broad spectrum toxicity. In practice, microbial based pesticides frequently are more selective towards the target pest(s), hence more environmentally desirable.
Some microbial pesticides are pathogenic (disease-causing) to the target pest, other types may act as competitors to the pest. In addition to living microorganisms, some microbial-based pesticides consist of toxins derived from microbes. Commercial formulations of the popular insecticide, Bacillus thuringiensis, for example, consist only of killed bacteria. The activity of such formulations comes from a toxin produced by the bacteria before killing.
