Scorias spongiosa
Encyclopedia
Scorias spongiosa is a sooty mould
fungus that grows on aphid
honeydew
. It is a member of the Capnodiaceae
family of ascomycete
fungi. It is found only on American beech trees, Fagus grandifolia.
of the beech blight aphid, Grylloprociphilus imbricator
. This aphid is found only on one host plant, the American beech tree, Fagus grandifolia, where it congregates on branches and twigs, creating copious amounts of honeydew that drip onto vegetation below. The large quantity of honeydew enables this fungus to grow to a large size, much bigger than other sooty mould fungi, which produce only a thin black layer on the surface of leaves. On tree trunks this fungus has been known to grow into a mass of hyphae
as big as a football, but it is more usual for the agglomeration on branches or twigs to reach a diameter of about fifteen centimetres.
s of Scorias spongiosa are borne by wind and rain and fall on the honeydew secretions found below the aphids. The first hyphal growth is straw coloured and unpigmented. The hyphae adhere to each other for short distances, diverging and re-adhering to form a loose stranded structure. Pigmentation begins to occur on the surfaces of outer strands and the stroma
begins to darken. The hyphae coalesce and form mycelial
strands which radiate outward and upward from the supporting structure. Flask-shaped, spore-bearing pycnidia
appear on the mycelia, which have a waxlike appearance: the matrix turns from brittle to soft as it absorbs moisture. As further quantities of honeydew accumulate, the fungus grows larger until it resembles a gelatinous sponge resting on the branches or leaves of the beech tree. Fully pigmented strands in the mature stoma produce bowl-shaped pseudothecia
and these outermost hyphae cease to grow. The inner strands continue growth and force their way to the exterior. Asexual
conidia are extruded in a slimy matrix in liquid droplets from the pycnidia. As time passes the stroma becomes a spongy black mass and produces sexual spores called ascospore
s in the pseudothecia, which remain embedded in the stroma.
Sooty mold
Sooty molds are Ascomycete fungi which grow on plant exudates and the sugary honeydew secreted by insects such as aphids, scales, the whitefly, and other insects which suck sap from their host plants. The name itself is descriptive, as sooty mold is a black, powdery coating adhering to the leaves...
fungus that grows on aphid
Aphid
Aphids, also known as plant lice and in Britain and the Commonwealth as greenflies, blackflies or whiteflies, are small sap sucking insects, and members of the superfamily Aphidoidea. Aphids are among the most destructive insect pests on cultivated plants in temperate regions...
honeydew
Honeydew (secretion)
Honeydew is a sugar-rich sticky liquid, secreted by aphids and some scale insects as they feed on plant sap. When their mouthpart penetrates the phloem, the sugary, high-pressure liquid is forced out of the gut's terminal opening. Honeydew is particularly common as a secretion in the Hemipteran...
. It is a member of the Capnodiaceae
Capnodiaceae
The Capnodiaceae are a family of fungi in the Ascomycota, class Dothideomycetes. Species in the family have a wdiespread distribution, and are especially prevalent in tropical and subtropical areas, as well as temperate rainforests.- Genera :...
family of ascomycete
Ascomycota
The Ascomycota are a Division/Phylum of the kingdom Fungi, and subkingdom Dikarya. Its members are commonly known as the Sac fungi. They are the largest phylum of Fungi, with over 64,000 species...
fungi. It is found only on American beech trees, Fagus grandifolia.
Overview
Scorias spongiosa is a specialist and grows exclusively on the honeydew formed by coloniesColony (biology)
In biology, a colony reference to several individual organisms of the same species living closely together, usually for mutual benefit, such as stronger defense or the ability to attack bigger prey. Some insects live only in colonies...
of the beech blight aphid, Grylloprociphilus imbricator
Beech blight aphid
The beech blight aphid is a small insect in the order Hemiptera that feeds on the sap of American beech trees. The aphids form dense colonies on small branches and the undersides of leaves....
. This aphid is found only on one host plant, the American beech tree, Fagus grandifolia, where it congregates on branches and twigs, creating copious amounts of honeydew that drip onto vegetation below. The large quantity of honeydew enables this fungus to grow to a large size, much bigger than other sooty mould fungi, which produce only a thin black layer on the surface of leaves. On tree trunks this fungus has been known to grow into a mass of hyphae
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
as big as a football, but it is more usual for the agglomeration on branches or twigs to reach a diameter of about fifteen centimetres.
Life cycle
The aphids accumulate in late summer and autumn, forming large colonies. SporeSpore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
s of Scorias spongiosa are borne by wind and rain and fall on the honeydew secretions found below the aphids. The first hyphal growth is straw coloured and unpigmented. The hyphae adhere to each other for short distances, diverging and re-adhering to form a loose stranded structure. Pigmentation begins to occur on the surfaces of outer strands and the stroma
Stroma (animal tissue)
In animal tissue, stroma refers to the connective, supportive framework of a biological cell, tissue, or organ.The stroma in animal tissue is contrasted with the parenchyma.Examples include:* Stroma of iris...
begins to darken. The hyphae coalesce and form mycelial
Mycelium
thumb|right|Fungal myceliaMycelium is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. The mass of hyphae is sometimes called shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelia are found in soil and on or within many other...
strands which radiate outward and upward from the supporting structure. Flask-shaped, spore-bearing pycnidia
Pycnidium
A pycnidium is an asexual fruiting body produced by mitosporic fungi in the form order Sphaeropsidales . It is often spherical or inversely pearshaped and its internal cavity is lined with conidiophores. When ripe, an opening generally appears at the top, through which the pycnidiospores escape....
appear on the mycelia, which have a waxlike appearance: the matrix turns from brittle to soft as it absorbs moisture. As further quantities of honeydew accumulate, the fungus grows larger until it resembles a gelatinous sponge resting on the branches or leaves of the beech tree. Fully pigmented strands in the mature stoma produce bowl-shaped pseudothecia
Ascocarp
An ascocarp, or ascoma , is the fruiting body of an ascomycete fungus. It consists of very tightly interwoven hyphae and may contain millions of asci, each of which typically contains eight ascospores...
and these outermost hyphae cease to grow. The inner strands continue growth and force their way to the exterior. Asexual
Asexual reproduction
Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy reduction, or fertilization. A more stringent definition is agamogenesis which is reproduction without...
conidia are extruded in a slimy matrix in liquid droplets from the pycnidia. As time passes the stroma becomes a spongy black mass and produces sexual spores called ascospore
Ascospore
An ascospore is a spore contained in an ascus or that was produced inside an ascus. This kind of spore is specific to fungi classified as ascomycetes ....
s in the pseudothecia, which remain embedded in the stroma.