Metarhizium anisopliae infected cockroach (PLoS)

Muscardine is a

disease A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pa ...

s. It is caused by many species of

entomopathogenic fungus An entomopathogenic fungus is a fungus that can kill or seriously disable insects. Typical life cycle These fungi usually attach to the external body surface of insects in the form of microscopic spores (usually asexual, mitosporic spores also ...

. Many muscardines are known for affecting

silkworm The domestic silk moth (''Bombyx mori''), is an insect from the moth family Bombycidae. It is the closest relative of '' Bombyx mandarina'', the wild silk moth. The silkworm is the larva or caterpillar of a silk moth. It is an economically ...

s.Singh, T. ''Principles And Techniques Of Silkworm Seed Production''. Discovery Publishing House. 2004. pg. 277. Muscardine may also be called calcino.Lu, Y. ''Silkworm Diseases''. FAO. 1991. pg. 37. While studying muscardine in silkworms in the 19th century,

Agostino Bassi Agostino Bassi, sometimes called de Lodi (25 September 1773 – 8 February 1856), was an Italian entomologist. He preceded Louis Pasteur in the discovery that microorganisms can be the cause of disease (the germ theory of disease). He discovered ...

found that the causal agent was a fungus. This was the first demonstration of the

germ theory of disease The germ theory of disease is the currently accepted scientific theory for many diseases. It states that microorganisms known as pathogens or "germs" can lead to disease. These small organisms, too small to be seen without magnification, invade ...

, the first time a microorganism was recognized as an animal pathogen.Mahr, S
Know Your Friends: The Entomopathogen ''Beauveria bassiana''.
''Midwest Biological Control News'' October, 1997. Volume IV, Number 10. There are many types of muscardine. They are often named for the color of the conidial layer each fungus leaves on its host.

Black muscardine

Black muscardine is caused by '' Beauveria brongniartti'' and ''

Metarhizium anisopliae ''Metarhizium robertsii'' formerly known as ''M. anisopliae'', and even earlier as ''Entomophthora anisopliae'' (basionym) is a fungus that grows naturally in soils throughout the world and causes disease in various insects by acting as a paras ...

''. ''Metarhizium'' species such as ''M. anisopliae'' can cause fatal disease in over 200 species of insect.Wang, C. and Y. Xia
Cover photo.
''PLoS Genetics'', January, 2011.

Brown muscardine

Aspergillosis Aspergillosis is a fungal infection of usually the lungs, caused by the genus ''Aspergillus'', a common mould that is breathed in frequently from the air around, but does not usually affect most people. It generally occurs in people with lung dis ...

of insects can be called brown muscardine. Over 10 ''

Aspergillus ' () is a genus consisting of several hundred mold species found in various climates worldwide. ''Aspergillus'' was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli. Viewing the fungi under a microscope, Mic ...

'' species can cause the disease, such as '' A. flavus'' and '' A. tamari''. The conidial layer may be brownish or greenish yellow.

Grassy muscardine

Grassy muscardine is caused by ''

Hirsutella necatrix ''Hirsutella'' is a genus of asexually reproducing fungi in the Ophiocordycipitaceae family. Originally described by French mycologist Narcisse Théophile Patouillard in 1892, this genus includes species that are pathogens of insects, mites and ne ...

''.Vega, F. E. and H. K. Kaya. ''Insect Pathology''. Academic Press. 2012. pg. 433. This fungus produces an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

that breaks down the

chitin Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...

in its host's body.Chernin, L., et al. (1997)
Chitinolytic activity of the acaropathogenic fungi ''Hirsutella thompsonii'' and ''Hirsutella necatrix''.
''Canadian Journal of Microbiology'' 43(5) 440-46.

Gray muscardine

Gray muscardine is caused by '' Isaria javanica''.

Green muscardine

Green muscardine is caused by ''

Nomuraea rileyi ''Metarhizium rileyi''Kepler, Humber, Bischoff, Rehner SA (2014) ''Mycologia'' 106(4): 824. is a species of entomopathogenic fungus in the family Clavicipitaceae The Clavicipitaceae are a family of fungi within the order Hypocreales. A 2008 ...

'' as well as ''

Metarhizium ''Metarhizium'' is a genus of entomopathogenic fungi in the Clavicipitaceae family. With the advent of genetic profiling, placing these fungi in proper taxa has now become possible. Most turn out to be the asexual forms (anamorphs) of fungi in ...

'' species. Keepers of silkworms recognize symptoms such as dark brownish lesions with lighter centers on the sides and back of the larva. At death the larva turns white and within a few days it is covered in a bright green fungal coating.

Orange muscardine

Orange muscardine is caused by '' Sterigmatocystis japonica''.

Penicillosis

Penicillosis of insects is considered a type of muscardine, particularly when caused by ''

Penicillium citrinum ''Penicillium citrinum'' is an anamorph, mesophilic fungus species of the genus of ''Penicillium'' which produces tanzawaic acid A-D, ACC, Mevastatin, Quinocitrinine A, Quinocitrinine B, and nephrotoxic citrinin. ''Penicillium citrinum'' is ...

'' and '' P. granulatum''.

Red muscardine

Red muscardine is caused by '' Sporosporella uvella'' and '' Isaria fumosoroseus''.

White muscardine

One of the best known forms is white muscardine, which is caused by ''

Beauveria bassiana ''Beauveria bassiana'' is a fungus that grows naturally in soils throughout the world and acts as a parasite on various arthropod species, causing white muscardine disease; it thus belongs to the entomopathogenic fungi. It is used as a biologic ...

''.White Muscardine Fungus.
Rice Knowledge Bank. International Rice Research Institute (IRRI). 2009. When suffering from white muscardine, an insect larva may become inactive and stop eating. The elasticity of its

cuticle A cuticle (), or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non- homologous, differing in their origin, structu ...

is lost and it may experience

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenter ...

and

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...

. As it dies it hardens. The fungus leaves the body of its host covered in powdery white conidia. The fungal layer is tough due to oxalate crystals, and this slows the decay of the body. When a

pupa A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in thei ...

is infected, it often mummifies. It shrinks and wrinkles before growing a fungal coating. In an adult moth, the body hardens and the wings drop off. WhiteMuscardineDiseaseGoldenSilkOrbWeaver

WhiteMuscardineDiseaseGoldenSilkOrbWeaver

During infection, the fungus absorbs water and nutrients from the host. The

hemolymph Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which ...

of the insect crystallizes and thickens. The fungus usually produces toxins, as well. After it kills the host, the fungus continues to absorb water from the body, causing it to harden further. Other insects prone to white muscardine include the

brown planthopper The brown planthopper (BPH), ''Nilaparvata lugens'' (Stål) (Hemiptera: Delphacidae) is a planthopper species that feeds on rice plants (''Oryza sativa'' L.). These insects are among the most important pests of rice, which is the major staple cro ...

and the diaprepes root weevil.Beavers, J. B., et al. (1972)
Two Muscardine fungi pathogenic to ''Diaprepes abbreviatus''.
''The Florida Entomologist'' 55(2) 117-120.

Yellow muscardine

Yellow muscardine is caused by '' Isaria farinosa''.

Yellow red muscardine

Yellow red muscardine is caused by '' Isaria fumosoroseus''. It can produce reddish patches on the external body and powdery masses of spores internally.

Control

Fungicidal Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or their spores. A fungistatic inhibits their growth. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality ...

agents such as

azadirachtin Azadirachtin, a chemical compound belonging to the limonoid group, is a secondary metabolite present in neem seeds. It is a highly oxidized tetranortriterpenoid which boasts a plethora of oxygen-bearing functional groups, including an enol ether, ...

and phytoallexin have been used against some muscardine pathogens.Vyas, R. V., et al. (1992)
Effect of some natural pesticides on entomogenous muscardine fungi.
''Indian J Exp Biol.'' 30(5) 435-6. Silkworm breeders dust their cages with

slaked lime Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca( OH)2. It is a colorless crystal or white powder and is produced when quicklime (calcium oxide) is mixed or slaked with water. It has m ...

to discourage fungal growth.Ravikumar, J., et al
Muscardine: a menace to silkworm in winter.
''The Hindu''. January 7, 2010. In India a dust of

chaff Chaff (; ) is the dry, scaly protective casing of the seeds of cereal grains or similar fine, dry, scaly plant material (such as scaly parts of flowers or finely chopped straw). Chaff is indigestible by humans, but livestock can eat it. In agri ...

soaked in

formalin Formaldehyde ( , ) ( systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section F ...

is applied to the larvae.Veeranna, G., et al. (1985)
Muscardine Disease – Precautionary Measures and Its Control.
Karnataka State Sericulture Research and Development Institute, Bangalore, Karnataka.

References

{{reflist Animal fungal diseases Insect diseases