Beauveria bassiana



Beauveria bassiana is a fungus that occurs naturally in soils throughout the world. It causes a fatal disease in various insects by acting as a parasite; it thus belongs to the entomopathogenic fungi. The species is named after the Italian entomologist Agostino Bassi who discovered it in 1835 as the cause of the muscardine disease of domesticated silkworms.

Beauveria bassiana (formerly also known as Tritirachium shiotae) is the anamorph (asexually reproducing form) of Cordyceps bassiana. The latter teleomorph (the sexually reproducing form) has been collected only in eastern Asia. In culture, B. bassiana grows as a white mold. On most common cultural media, it produces many dry, powdery conidia in distinctive white spore balls. Each spore ball is composed of a cluster of conidiogenous cells. The conidiogenous cells of B. bassiana are short and ovoid, and terminate in a narrow apical extension called a rachis. The rachis elongates after each conidium is produced, resulting in a long zig-zag extension. The conidia are single-celled, haploid, and hydrophobic.

The name B. bassiana has long been used to describe a complex of morphologically similar and closely related species. Rehner and Buckley have shown that B. bassiana consists of many distinct lineages that should be recognized as distinct phylogenetic species.

The insect disease caused by the fungus is called white muscardine disease. When the microscopic spores of the fungus come into contact with the body of an insect host, they germinate, penetrate the cuticle, and grow inside, killing the insect within a matter of days. Afterwards a white mold emerges from the cadaver and produces new spores. A typical isolate of B. bassiana can attack a broad range of insects; various isolates differ in their host range. The factors responsible for host susceptibility are not known.

Beauveria bassiana parasitizing the Colorado potato beetle has been reported to be, in turn, the host of a mycoparasitic fungus Syspastospora parasitica. This organism also attacks related insect-pathogenic species of the Clavicipitaceae.

Use in biological control of insects
Beauveria bassiana can be used as a biological insecticide to control a number of pests such as termites, whitefly, and many other insects. Its use in the control of the malaria-transmitting mosquitos is under investigation. As an insecticide, the spores are sprayed on affected crops as an emulsified suspension or wettable powder or applied to mosquito nets as a malaria control agent. Beauveria bassiana parasitizes a very wide range of arthropod hosts, and so should be considered a nonselective pesticide. It should not be applied to flowers visited by pollinating insects.

Known targets include  :


 * Aphids
 * Whiteflies
 * Bugs
 * Mealybugs
 * Psyllids
 * Lygus bugs
 * Chinch bug


 * Grasshoppers
 * Thrips
 * Termites
 * Fire ants
 * Flies
 * Fungal gnats
 * Shoreflies


 * Beetles
 * Coffee borer beetle
 * Colorado potato beetle
 * Mexican bean beetle
 * Japanese beetle
 * Boll weevil
 * Cereal leaf beetle
 * Bark beetles
 * Black Vine Weevil
 * Strawberry root weevil


 * Caterpillars
 * European corn borer
 * Codling moth
 * Douglas fir tussock moth
 * Silkworm


 * Mites

The fungus rarely infects humans or other animals, so it is generally considered safe as an insecticide. However, at least one case of human infection by B. bassiana has been reported in a person with a suppressed immune system. Additionally, like any powder, the spores may exacerbate breathing difficulties. Wagner and Lewis reported the ability of B. bassiana to grow as an endophyte in corn.