Muscardine is a

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

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

s. It is caused by many species of entomopathogenic fungus. Many muscardines are known for affecting

silkworm ''Bombyx mori'', commonly known as the domestic silk moth, is a moth species belonging to the family Bombycidae. It is the closest relative of '' Bombyx mandarina'', the wild silk moth. Silkworms are the larvae of silk moths. The silkworm is of ...

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 discovere ...

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 cause disease. These small organisms, which are too small to be seen without magnification, ...

, 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 anisopliae'' is a fungus, the type species in the ''Metarhizium'' genus. It grows naturally in soils throughout the world and causes disease in various insects by acting as a parasitoid. Ilya Ilyich Mechnikov, Ilya I. Mechnikov nam ...

''. ''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 mold that is breathed in frequently from the air, but does not usually affect most people. It generally occurs in people with lung diseases su ...

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, Miche ...

'' 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 An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

that breaks down the

chitin Chitin (carbon, C8hydrogen, H13oxygen, O5nitrogen, N)n ( ) is a long-chain polymer of N-Acetylglucosamine, ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is the second most abundant polysaccharide in nature (behind only cell ...

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 disease is the presentation of a fungal infection of insects caused by members of the '' Metarhizium'' genus (now including '' Nomuraea rileyi''), because of the green colour of their

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

s. Once the fungus has killed its host,

mycelia Mycelium (: mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Its normal form is that of branched, slender, entangled, anastomosing, hyaline threads. Fungal colonies composed of mycelium are fo ...

invade the host's body and, under humid conditions, the insect cuticle becomes covered with a layer of green spores, hence the name of the disease. It was originally discovered as a pest of silk worms, upon which it was highly lethal. To insect mycologists and microbial control specialists, "green muscardine" refers to fungal infection caused by ''Metarhizium'' spp., whereas in

sericulture Sericulture, or silk farming, is the cultivation of silkworms to produce silk. Although there are several commercial species of silkworms, the caterpillar of the Bombyx mori, domestic silkmoth is the most widely used and intensively studied silkwo ...

, "green muscardine" refers to a similar fungal infection caused by '' Nomuraea rileyi''. Green muscardine has been identified as disease of over 200 known insect species.

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'' 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''.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, puking and throwing up) is the 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, gastroenteritis, pre ...

and

diarrhea Diarrhea (American English), also spelled diarrhoea or diarrhœa (British English), is the condition of having at least three loose, liquid, or watery bowel movements in a day. It often lasts for a few days and can result in dehydration d ...

. 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 (; : 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 their life cycle, the stages th ...

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 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 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 ''Cordyceps'' is a genus of ascomycete fungi (sac fungi) that includes over 260 species worldwide, many of which are parasitic. Diverse variants of cordyceps have had more than 1,500 years of use in Chinese medicine. Most ''Cordyceps'' species ...

''.

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 agents such as azadirachtin 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 with water. Annually, approxim ...

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 dry, scale-like plant material such as the protective seed casings of cereal grains, the scale-like parts of flowers, or finely chopped straw. Chaff cannot be digested by humans, but it may be fed to livestock, ploughed into soil ...

soaked in

formalin Formaldehyde ( , ) (systematic name methanal) is an organic compound with the chemical formula and structure , more precisely . The compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde. It is stored as ...

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