''Beauveria bassiana'' is a
fungus
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately fr ...
that grows naturally in soils throughout the world and acts as a
parasite
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson h ...
on various
arthropod species, causing white muscardine disease; it thus belongs to the
entomopathogenic fungi. It is used as a biological
insecticide to control a number of pests, including
termites,
thrips,
whiteflies,
aphids and various
beetles. Its use in the control of
bedbug
Bed bugs are insects from the genus ''Cimex'' that feed on blood, usually at night. Their bites can result in a number of health impacts including skin rashes, psychological effects, and allergic symptoms. Bed bug bites may lead to skin changes ...
s
and
malaria-transmitting
mosquitos is under investigation.
[Donald G. McNeil Jr.]
Fungus Fatal to Mosquito May Aid Global War on Malaria
''The New York Times'', 10 June 2005
Discovery and name
The species is named after the
Italian entomologist Agostino Bassi, who discovered it in 1835 as the cause of the muscardine disease which then led to carriers transmitting it by airborne means, and later the same year it was named ''Botrytis bassiana'' by
Giuseppe Gabriel Balsamo-Crivelli. In 1911
Jean Beauverie did further study and the next year
Jean Paul Vuillemin made it the
type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specim ...
of his new ''Beauveria''.
It was formerly also known as ''Tritirachium shiotae''. The name ''B. bassiana'' has long been used to describe a
species complex of morphologically similar and closely related
isolates. Rehner and Buckley have shown that ''B. bassiana'' consists of many distinct lineages that should be recognized as distinct phylogenetic species and the genus ''
Beauveria'' was redescribed with a proposed type for ''B. bassiana'' in 2011. In light of this work and the known existence of
cryptic species
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each ot ...
, it is important to characterise
isolates used to develop
biological insecticides.
Relation to ''Cordyceps'' and other fungi
''Beauveria bassiana'' is the
anamorph (asexually reproducing form) of ''
Cordyceps bassiana''. The latter
teleomorph (the sexually reproducing form) has been collected only in eastern Asia.
White muscardine disease
The
insect disease caused by the fungus is a
muscardine
Muscardine is a disease of insects. It is caused by many species of entomopathogenic fungus. Many muscardines are known for affecting silkworms.Singh, T. ''Principles And Techniques Of Silkworm Seed Production''. Discovery Publishing House. 2004. ...
which has been 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.
Morphology of the fungus
In culture, ''B. bassiana'' grows as a white
mould. 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.
Use in biological control of insects
''Beauveria bassiana'' can be used as a
biological insecticide
A Biopesticide is a biological substance or organism that damages, kills, or repels organisms seens as pests. Biological pest management intervention involves predatory, parasitic, or chemical relationships.
They are obtained from organisms inclu ...
to control a number of pests such as
termites,
whiteflies, and many other insects. Its use in the control of
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 mosquito control agent.
As a species, ''Beauveria bassiana'' parasitizes a very wide range of arthropod hosts. However, different strains vary in their host ranges, some having rather narrow ranges, like strain Bba 5653 that is very virulent to the larvae of the diamondback moth and kills only few other types of caterpillars. Some strains do have a wide host range and should, therefore, be considered nonselective biological insecticides. These should not be applied to flowers visited by ]pollinating
Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, a ...
insects.
Known targets include:
* Aphids
* Whiteflies
* Mealybugs
* Psyllids
** Chinch bug
** Lygus bugs
* Grasshoppers
* Stink bugs ('' Halyomorpha halys'')
* Thrips
* Termites
* Fire ants
* Flies
* Stem borers
** Fungal gnats
** Shoreflies
* Beetle
Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
s
** Bark beetle
** Black vine weevil
** Boll weevil
** Cereal leaf beetle
** Coffee berry borer
** Colorado potato beetle
** Emerald ash borer (in conjunction with the parasitoid wasp '' Tetrastichus planipennisi'')
** Japanese beetle
The Japanese beetle (''Popillia japonica'') is a species of scarab beetle. The adult measures in length and in width, has iridescent copper-colored elytra and a green thorax and head. It is not very destructive in Japan (where it is control ...
** Mexican bean beetle
** Red palm weevil
The palm weevil ''Rhynchophorus ferrugineus'' is one of two species of snout beetle known as the red palm weevil, Asian palm weevil or sago palm weevil. The adult beetles are relatively large, ranging between long, and are usually a rusty red c ...
** Strawberry root weevil
* Caterpillars
** Codling moth
The codling moth (''Cydia pomonella'') is a member of the Lepidopteran family Tortricidae. They are major pests to agricultural crops, mainly fruits such as apples and pears. Because the larvae are not able to feed on leaves, they are highly ...
** Douglas fir tussock moth
** European corn borer
The European corn borer (''Ostrinia nubilalis''), also known as the European corn worm or European high-flyer, is a moth of the family Crambidae which includes other grass moths. It is a pest of grain, particularly maize (''Zea mays''). The ...
** Invasive silkworms
** Apple clearwing moth
* 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, the spores may exacerbate breathing difficulties. Wagner and Lewis reported the ability of ''B. bassiana'' to grow as an endophyte in corn.
A fungus attributed to be ''B. bassiana'' was observed to cause infections in a captive American alligator and ''B. bassiana'' was implicated in causing a pulmonary disease in captive tortoises. The reptiles were in captivity and under temperature stress which may explain their susceptibility to the fungus. When a tortoise was kept at 22°C and injected with 0.5 mL of 106 spores of ''B. bassiana'' into the lung, no mortality was observed, while a second contaminated tortoise died when kept only at 16°C.
Preliminary research has shown the fungus is 100% effective in eliminating bed bugs
Bed bugs are insects from the genus ''Cimex'' that feed on blood, usually at night. Their bites can result in a number of health impacts including skin rashes, psychological effects, and allergic symptoms. Bed bug bites may lead to skin changes ...
exposed to cotton fabric sprayed with fungus spores. It is also effective against bed bug colonies due to ''B. bassiana'' carried by infected bugs back to their harborages. The tested strain of B bassiana caused rapid mortality (3 - 5 days) after short-term exposure. In a 2017 follow-up study, pyrethroid
A pyrethroid is an organic compound similar to the natural pyrethrins, which are produced by the flowers of pyrethrums ('' Chrysanthemum cinerariaefolium'' and '' C. coccineum''). Pyrethroids are used as commercial and household insecticides. ...
-resistant bed bugs had >94% mortality after treatment with a commercial preparation of B. bassiana.
A microevolutionary experiment in 2013 showed that the Greater wax moth ('' Galleria mellonella'') was able to adapt its defense mechanisms during 25 generations, while being under constant selective pressure from the fungus ''B. bassiana''. The moth developed resistance, but apparently, at a cost.
Containment leak
In March 2013, genetically modified ''Beauveria bassiana'' was found in a number of research laboratories and greenhouses outside of a designated containment area at Lincoln University in Christchurch, New Zealand. The Ministry for Primary Industries investigated the leak.
See also
* Biological insecticides
* '' Metarhizium ''spp. which cause "green muscardine" disease
References
Further reading
*
*
{{Taxonbar, from=Q2345333
Biopesticides
Clavicipitaceae
Fungi described in 1836
Malaria
Parasitic fungi