Stigmatomycosis is a fungal disease that occurs in a number of crops, such as

cotton Cotton (), first recorded in ancient India, is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure ...

soybean The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean. Soy is a staple crop, the world's most grown legume, and an important animal feed. Soy is a key source o ...

pecan The pecan ( , , ; ''Carya illinoinensis'') is a species of hickory native to the Southern United States and northern Mexico in the region of the Mississippi River. The tree is cultivated for its seed primarily in the U.S. states of Georgia ( ...

pomegranate The pomegranate (''Punica granatum'') is a fruit-bearing deciduous shrub in the family Lythraceae, subfamily Punica, Punicoideae, that grows between tall. Rich in symbolic and mythological associations in many cultures, it is thought to have o ...

citrus ''Citrus'' is a genus of flowering trees and shrubs in the family Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, mandarins, lemons, grapefruits, pomelos, and limes. ''Citrus'' is nativ ...

, and

pistachio The pistachio (, ; ''Pistacia vera'') is a small to medium-sized tree of the Anacardiaceae, cashew family, originating in Iran. The tree produces nut (fruit)#Culinary definition and uses, seeds that are widely consumed as food. In 2022, world ...

. It has been reported on pistachio in

Greece Greece, officially the Hellenic Republic, is a country in Southeast Europe. Located on the southern tip of the Balkan peninsula, it shares land borders with Albania to the northwest, North Macedonia and Bulgaria to the north, and Turkey to th ...

Iran Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the nort ...

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

, and is frequently a problem in California pistachio orchards severely infested by

hemiptera Hemiptera (; ) is an order of insects, commonly called true bugs, comprising more than 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from ...

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. In a 1989 survey in

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, fruit with stigmatomycosis were found in 90% of samples collected from late June to mid-September and from all growing areas.

Symptoms

Stigmatomycosis is characterized by a wet, smelly, rancid, slimy

kernel Kernel may refer to: Computing * Kernel (operating system), the central component of most operating systems * Kernel (image processing), a matrix used for image convolution * Compute kernel, in GPGPU programming * Kernel method, in machine learnin ...

. Kernels with stigmatomycosis can be 1) small, dark green and partially developed with a brown

funiculus Funiculus (''Latin'' for "slender rope") is any cord-like structure in anatomy or biology, and may refer to: Anatomy * the spermatic cord formed by the vas deferens and surrounding tissue * the umbilical cord attaching a fetus to the placenta dur ...

, 2) well-developed, dark green and rancid, or 3) full-sized but abnormal, being white or light yellow and jelly-like, with a lobed appearance. In contrast, symptoms of kernel

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...

, which is caused by large

ns, are dry, punky, brown areas in the kernel. Sometimes, kernel necrosis and stigmatomycosis symptoms can be present in the same fruit.

Causal organisms

Stigmatomycosis is caused by the

filamentous fungi A mold () or mould () is one of the structures that certain fungi can form. The dust-like, colored appearance of molds is due to the formation of spores containing fungal secondary metabolites. The spores are the dispersal units of the fungi ...

Ashbya gossypii (also known as ''Ashbya gossypii'') is a filamentous fungus or Mold (fungus), mold closely related to yeast, but growing exclusively in a filamentous way. It was originally isolated from cotton as a pathogen causing stigmatomycosis by Sydney Fr ...

,'' '' Eremothecium coryli'' (syn. ''Nematospora coryli''), and ''

Aureobasidium pullulans ''Aureobasidium pullulans'' is a ubiquitous and generalistic black, yeast-like fungus that can be found in different environments (e.g. soil, water, air and limestone). It is well known as a naturally occurring epiphyte or endophyte of a wide ra ...

''. All of them belong to the phylum of

ascomycetes Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The de ...

Disease cycle and epidemiology

The fungi causing stigmatomycosis are associated with

n insects of the stinkbug families

Pentatomidae Pentatomidae is a family of insects belonging to the order Hemiptera, generally called shield bugs or stink bugs. Pentatomidae is the largest family in the superfamily Pentatomoidea, and contains around 900 genera and over 4700 species.Robert G ...

and

Coreidae Coreidae is a large family (biology), family of predominantly sap-sucking insects in the Hemipteran suborder Heteroptera. The name "Coreidae" derives from the genus ''Coreus'', which derives from the Ancient Greek () meaning bedbug. As a fam ...

. Hemipterans are common

pests PESTS was an anonymous American activist group formed in 1986 to critique racism, tokenism, and exclusion in the art world. PESTS produced newsletters, posters, and other print material highlighting examples of discrimination in gallery represent ...

orchards, and up to ten species have been found in

pistachio orchards. Three common stinkbug pests, ''

Thyanta pallidovirens ''Thyanta pallidovirens'', the red-shouldered stink bug, is a species of stink bug in the family Pentatomidae. It is found in Central America Central America is a subregion of North America. Its political boundaries are defined as borde ...

'' (Western red-shouldered stinkbug), '' Chlorochroa uhleri,'' '' Chlorochroa ligata,'' and a leaffooted bug, '' Leptoglossus clypealis'' (Coreidae), experimentally transmitted '' E. coryli,'' which caused typical

symptoms Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature ...

of stigmatomycosis in pistachio

kernels Kernel may refer to: Computing * Kernel (operating system), the central component of most operating systems * Kernel (image processing), a matrix used for image convolution * Compute kernel, in GPGPU programming * Kernel method, in machine learnin ...

. Symptoms first appear in late June after pistachio shells have hardened, but the disease becomes frequent in July through September, a period that coincides with kernel development. Smaller hemipterans, such as ''

Lygus The genus ''Lygus'' includes over 40 species of plant-feeding insects in the family Miridae. The term lygus bug is used for any member of genus ''Lygus''. Species At one time, nearly 200 species were classified as genus ''Lygus'', but most of th ...

'' and ''

Calocoris ''Calocoris'' is a genus of true bugs in the Miridae The Miridae are a large and diverse insect family at one time known by the Synonym (taxonomy), taxonomic synonym Capsidae. Species in the family may be referred to as capsid bugs or "mirid ...

'', may carry but not transmit the

pathogens In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term ...

because they are unable to puncture the firm fruit

pericarp Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. Fruitlike structures may develop directly from the seed itself rather th ...

after the second part of May. Stigmatomycosis and kernel

are worse in orchards irrigated by sprinklers than in those irrigated by drip, microjets, or flood. This suggests either greater humidity requirements for infection, more activity of hemipterans in sprinkler-irrigated orchards, or more abundant pathogen

propagules In biology, a propagule is any material that functions in propagating an organism to the next stage in its life cycle, such as by dispersal. The propagule is usually distinct in form from the parent organism. Propagules are produced by organisms ...

Control

Fungicide Fungicides are pesticides used to kill parasitic fungi or their spores. Fungi can cause serious damage in agriculture, resulting in losses of yield and quality. Fungicides are used both in agriculture and to fight fungal infections in animals, ...

s do not control stigmatomycosis but

insecticide Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ...

s reduce hemipteran

vector Vector most often refers to: * Euclidean vector, a quantity with a magnitude and a direction * Disease vector, an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematics a ...

populations and the incidence of stigmatomycosis.

References

* Themis J. Michailides. {{deadlink, date=September 2023 Cotton diseases Fungal citrus diseases Soybean diseases Nut tree diseases Fungal fruit diseases Fruit tree diseases