[1][4][5] In nature, this necrotrophic wound pathogen grows in filaments and reproduces asexually through the production of conidiophores and conidia.

[1] Alongside its pathogenic life cycle, P. digitatum is also involved in other human, animal and plant interactions and is currently being used in the production of immunologically based mycological detection assays for the food industry.

[10] As a species, P. digitatum was first noted as Aspergillus digitatus by Christiaan Hendrik Persoon in 1794 who later adopted the name Monilia digitata in Synopsis methodica fungorum (1801).

[12] However, the current binomial name comes from the writings of Pier Andrea Saccardo, particularly Fungi italici autographie delineati et colorati (1881).

[12] In nature, P. digitatum adopts a filamentous vegetative growth form, producing narrow, septate hyphae.

[1] On Malt Extract Agar medium at 25 °C, growth is rapid yet rare, forming a velvety surface.

[1] Penicillium digitatum is found in the soil of areas cultivating citrus fruit, predominating in high temperature regions.

[1][2] In nature, it is often found alongside the fruits it infects, making species within the genus Citrus its main ecosystem.

[1] Thiamine, on the other hand, has been observed to accelerate fungal growth with the effect being co-metabolically enhanced in the presence of tyrosine, casein or zinc metal.

[8] Production of ethylene via the citric acid cycle has been observed in static cultures and is suggested to be connected to mycelial development.

[15] Production of mycotoxins or secondary metabolites by P. digitatum has not been observed although this species has been shown to be toxic to both shrimp and chicken embryos.

[17] However, being one of the most common producers of indoor moulds, certain species can become pathogenic upon long-term exposure as well as for individuals who are immunocompromised or hyper-sensitized to certain parts of the fungus.

[17][18] Spores, proteolytic enzymes and glycoproteins are amongst the components commonly reported as allergens in humans and animal models.

[18] With respect to P. digitatum, this species is known to cause generalized mycosis in humans, although the incidence of such events are very low.

[17] Various studies have also noted a presence of circulating antibodies to the extracellular polysaccharide of P. digitatum in both human and rabbit sera.

[21] Its widespread impact relates to the post-harvest disease it causes in citrus fruits known as green rot or mould.

[7] As a wound pathogen, the disease cycle begins when P. digitatum conidia germinate with release of water and nutrients from the site of injury on the fruit surface.

[2][3] Near the end of the disease cycle, the fruit eventually decreases in size and develops into an empty, dry shell.

[2] This end result is commonly used to distinguish P. digitatum infections from those of P. italicum which produce a blue-green mould and ultimately render the fruit slimy.

[3] Injuries can also be caused by other events such as frost and insect bites, and can be as minor as damage to fruit skin oil glands.

[1][23] In addition, P. digitatum has also been observed to modify plant defense mechanisms, such as phenylalanine ammonia lyase activity, in the citrus fruits it infects.

[9] Besides its pathogenic interactions, P. digitatum has also been implicated in naturally accelerating the ripening of green fruits and causing epinastic responses in various plants such as potato, tomato and sunflowers.

[1] In terms of the export market, Generally recognized as safe (GRAS) substances are currently being explored as alternatives.

[24] Alternative measures of control include essential oils such as Syzygium aromaticum and Lippia javanica, ultraviolet light, gamma-irradiation,[5] X-rays curing, vapour heat, and cell-penetrating anti-fungal peptides.

Closely related species in the genus Pencillium can be resolved through this approach by using Creatine Sucrose Neutral Agar.

[1] The genomes of many species belonging to the genus Penicillium remain to be sequenced however, limiting the applicability of such methods.