Cryptococcus fagisuga

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Cryptococcus fagisuga
Beechscalenymph.jpg
Nymph
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Suborder: Sternorrhyncha
Family: Eriococcidae
Genus: Cryptococcus
Species:
C. fagisuga
Binomial name
Cryptococcus fagisuga
Lindinger, 1936 [1]
Synonyms [2]
  • Coccus fagiBaerensprung, 1849
  • Cryptococcus fagiDouglas, 1890
  • Eriococcus fagi Perrier, 1926
  • Kermes fagi Lindinger, 1957
  • Pseudococcus fagi Douglas, 1886

Cryptococcus fagisuga, commonly known as the beech scale or woolly beech scale, is a felted scale insect in the superfamily Coccoidea that infests beech trees of the genus Fagus . It is associated with the transmission of beech bark disease [3] because the puncture holes it makes in the bark allow entry of pathogenic fungi which have been identified as Nectria coccinea var. faginata and sometimes Nectria galligena . [4] [5]

Contents

History and distribution

Cryptococcus fagisuga aka Beech bark disease has been recorded as affecting common beech trees, Fagus sylvatica , in Europe since before 1849. Until 1914 it was thought that the beech scale insect itself was responsible for the disease. Subsequently it was discovered that a fungus, then identified as Neonectria ditissima , was in fact killing the trees infested by the scale. Around 1890 the scale insect was accidentally introduced into Nova Scotia. By 1932, the scale and its associated Neonectria fungus had spread to many areas of the Maritime Provinces and parts of eastern and south central Maine. It continues to spread in North America and is now found in Quebec, Ontario, New England, New York, New Jersey, Pennsylvania and West Virginia. [5] Attempts are being made to discover the geographic origin of beech scale in order to try to identify any natural enemies that might hold promise for its biological control. From these studies and associated ribosomal DNA analysis, it seems likely that the pest originated in the region of northeast Greece, northern Iran, the Caucasus and the Black Sea drainage basin on the host beech subspecies F. sylvatica orientalis. [6]

Description

Adult scales are elliptical and about one millimetre long and are covered by a cream coloured, cottony wax secretion. They have reddish-brown eyes, no wings, rudimentary antennae and legs, and numerous minute wax-secreting glands. The stylet through which they suck sap can be up to two millimetres long. [5]

Life cycle

There are no male beech scale insects and the females reproduce by parthenogenesis. From midsummer onwards, they deposit four to eight pale yellow eggs, attached to each other in strings end to end, on the bark of the trees where they have been feeding. The wingless larvae that hatch out about twenty days later are known as crawlers or nymphs. They have well-developed legs and short antennae. Some remain concealed under the female, which dies after the eggs are laid, and others disperse to cracks and crevices on the tree. A few get washed down or fall to the ground and most of these perish. Occasionally one may find its way to another beech tree, perhaps wafted there by the wind or on the foot of a bird, and founds a new colony. Having found a location on a suitable tree, the crawler forces its tubular stylet into the bark and starts to feed. At this stage, it moults and becomes a second-stage, legless nymph, and will remain sedentary for the rest of its life. It secretes wax from glands and is soon covered in a protective coating of wool-like material. After overwintering it completes a second moult in the spring to become a mature female. [5]

Biology

The beech scale is monophagous, being found only on beech trees, and sucks sap from the parenchyme tissue of the bark. The small wounds produced when it feeds allow the Nectria fungi to invade infested trees. [4] The insect colonises beech trees that are aged at least thirty years. Studies have shown that younger trees produce defensive chemicals which deter infestation. [7] A ladybird beetle Chilocorus stigma feeds on this scale and is common throughout most of the Eastern United States, but this predator does not reduce scale populations sufficiently to control infestations. Persistent severely cold weather may kill beech scale and air temperatures of -37 °C have been shown to be lethal to insects not protected by snow. [5] Although trees are weakened when supporting scale colonies, this does not usually cause mortality, which only occurs after the trees have been invaded by the Nectria fungi. It usually takes three to six years of infestation by the scale insect before the fungus reaches critical levels. Where beech bark disease becomes established, most of the larger trees will die. Some trees seem to be partially resistant to the disease and a small number seem to be completely resistant. This may be partly due to the fact that trees with smooth bark provide fewer cracks and crevices in which the scale insect can flourish. [8] [9]

Related Research Articles

<span class="mw-page-title-main">Hemiptera</span> Order of insects often called true bugs

Hemiptera is an order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from 1 mm (0.04 in) to around 15 cm (6 in), and share a common arrangement of piercing-sucking mouthparts. The name "true bugs" is often limited to the suborder Heteroptera.

<i>Fagus grandifolia</i> Species of tree

Fagus grandifolia, the American beech or North American beech, is the only species of beech native to North America. Its current range comprises the eastern United States, isolated pockets of Mexico and southeastern Canada. Prior to the glacial maximum of the Pleistocene epoch, the tree flourished over most of North America, reaching California.

<span class="mw-page-title-main">Scale insect</span> Superfamily of insects

Scale insects are small insects of the order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient grouping than the superfamily Coccoidea due to taxonomic uncertainties. Adult females typically have soft bodies and no limbs, and are concealed underneath domed scales, extruding quantities of wax for protection. Some species are hermaphroditic, with a combined ovotestis instead of separate ovaries and testes. Males, in the species where they occur, have legs and sometimes wings, and resemble small flies. Scale insects are herbivores, piercing plant tissues with their mouthparts and remaining in one place, feeding on sap. The excess fluid they imbibe is secreted as honeydew on which sooty mold tends to grow. The insects often have a mutualistic relationship with ants, which feed on the honeydew and protect them from predators. There are about 8,000 described species.

<span class="mw-page-title-main">Bark beetle</span> Subfamily of beetles

A bark beetle is the common name for the subfamily of beetles Scolytinae. Previously, this was considered a distinct family (Scolytidae), but is now understood to be a specialized clade of the "true weevil" family (Curculionidae). Although the term "bark beetle" refers to the fact that many species feed in the inner bark (phloem) layer of trees, the subfamily also has many species with other lifestyles, including some that bore into wood, feed in fruit and seeds, or tunnel into herbaceous plants. Well-known species are members of the type genus Scolytus, namely the European elm bark beetle S. multistriatus and the large elm bark beetle S. scolytus, which like the American elm bark beetle Hylurgopinus rufipes, transmit Dutch elm disease fungi (Ophiostoma). The mountain pine beetle Dendroctonus ponderosae, southern pine beetle Dendroctonus frontalis, and their near relatives are major pests of conifer forests in North America. A similarly aggressive species in Europe is the spruce ips Ips typographus. A tiny bark beetle, the coffee berry borer, Hypothenemus hampei is a major pest on coffee plantations around the world.

<i>Lepidosaphes ulmi</i> Species of true bug

Lepidosaphes ulmi also known as apple mussel scale or oystershell scale is a widely invasive scale insect that is a pest of trees and woody plants. The small insects attach themselves to bark and cause injury by sucking the tree's sap; this metabolic drain on the plant may kill a branch or the entire tree.

<span class="mw-page-title-main">San Jose scale</span> Species of true bug

The San Jose scale or China scale,, is a hemipterous insect in the family Diaspididae. It is an agricultural pest as it causes damage and crop losses to many fruit crops. In 1914, this species became the first documented case of insecticide resistance.

<span class="mw-page-title-main">Beech bark disease</span> Disease of beech trees

Beech bark disease is a disease that causes mortality and defects in beech trees in the eastern United States, Canada and Europe. In North America, the disease occurs after extensive bark invasion by Xylococculus betulae and the beech scale insect, Cryptococcus fagisuga. Through a presently unknown mechanism, excessive feeding by this insect causes two different fungi to produce annual cankers on the bark of the tree. The continuous formation of lesions around the tree eventually girdles it, resulting in canopy death. In Europe, N. coccinea is the primary fungus causing the infection. Infection in European trees occurs in the same manner as it does in North American trees. Though the disease still appears in Europe, it is less serious today than it once was.

<i>Nectria coccinea</i> Species of fungus

Nectria coccinea is a fungal plant pathogen. The variant Nectria coccinea var. faginata causes beech bark disease, and can infect the tree via the feeding holes made by the beech scale insect Cryptococcus fagisuga.

<i>Cinara cupressi</i> Species of true bug

Cinara cupressi, the cypress aphid, is a brownish soft-bodied aphid. It sucks sap from twigs of conifers, and can cause damage to the tree, ranging from discoloring of the affected twig to the death of the tree. This insect appears to have originated in the Middle East and has been increasing its range and is considered to be an invasive species in Africa and Europe. It has been included in the List of the world's 100 worst invasive species.

<i>Coccus viridis</i> Species of true bug

Coccus viridis is a soft scale insect in the family Coccidae with a wide host range. It is commonly known as green scale or sometimes coffee green scale because it is a major pest of coffee crops throughout the world.

<span class="mw-page-title-main">Eriococcidae</span> Family of true bugs

Eriococcidae is a family of scale insects in the order Hemiptera. They are commonly known as felt scales or eriococcids. As of 2023, there are 109 genera and 681 species. Each species is usually specific to a different plant host, or closely related group of hosts.

<i>Coccus hesperidum</i> Species of true bug

Coccus hesperidum is a soft scale insect in the family Coccidae with a wide host range. It is commonly known as brown soft scale. It has a cosmopolitan distribution and feeds on many different host plants. It is an agricultural pest, particularly of citrus and commercial greenhouse crops.

<i>Eriosoma lanigerum</i> Species of true bug

Eriosoma lanigerum, the woolly apple aphid, woolly aphid or American blight, is an aphid in the superfamily Aphidoidea in the order Hemiptera. It is a true bug and sucks sap from plants.

<span class="mw-page-title-main">Forest disturbance by invasive insects and diseases in the United States</span>

Species which are not native to a forest ecosystem can act as an agent of disturbance, changing forest dynamics as they invade and spread. Invasive insects and pathogens (diseases) are introduced to the United States through international trade, and spread through means of natural and human-dispersal. Invasive insects and pathogens are a serious threat to many forests in the United States and have decimated populations of several tree species, including American chestnut, American elm, eastern hemlock, whitebark pine, and the native ash species. The loss of these tree species is typically rapid with both short and long-term impacts to the forest ecosystem.

<i>Aspidiotus destructor</i> Species of true bug

Aspidiotus destructor, the coconut scale, is a species of armoured scale insect in the family Diaspididae, found in many tropical and subtropical parts of the world. It is a serious pest of coconut and banana, and attacks a range of other fruiting trees and ornamental plants.

<i>Phyllaphis fagi</i> Species of true bug

Phyllaphis fagi, the woolly beech aphid, is a species of aphid in the family Aphididae.

<i>Ceroplastes rubens</i> Species of true bug

Ceroplastes rubens, known generally as the red wax scale or pink wax scale, is a species of soft scale insect in the family Coccidae. It is native to Australia but has been introduced to other countries, including New Caledonia, Japan, China, Poland and the United States.

<i>Diaspidiotus juglansregiae</i> Species of scale insect

Diaspidiotus juglansregiae, commonly known as the walnut scale, is a species of armoured scale insect in the family Diaspididae. It is native to North America where it feeds on a wide range of ornamental and forest trees and bushes.

<i>Neonectria faginata</i> Species of fungus

Neonectria faginata is a species of fungus that affects Beech trees in North America. Neonectria faginata, along with Neonectria ditissima, are the cause of beech bark disease in trees that have already been affected by beech scale Cryptococcus fagisuga.

<i>Eriococcus orariensis</i> Species of insect

Eriococcus orariensis, commonly known as the mānuka blight, is a felt scale insect in the genus Eriococcus. It is native to Australia, but was discovered in New Zealand in 1937 after being accidentally introduced to the country.

References

  1. Uniprot
  2. Zipcode Zoo
  3. Campbell, Faith (August 2004). "Beech Bark Disease". Don't Move Firewood.
  4. 1 2 Houston, D R (1994). "Major New Tree Disease Epidemics: Beech Bark Disease". Annual Review of Phytopathology. 32: 75–87. doi:10.1146/annurev.py.32.090194.000451.
  5. 1 2 3 4 5 U.S. Department of Agriculture, Forest Service [ permanent dead link ][ full citation needed ]
  6. Gwiazdowski, Rodger A; Van Driesche, Roy G; Desnoyers, Adrienne; Lyon, Suzanne; Wu, San-an; Kamata, Naotoa; Normark, Benjamin B (2006). "Possible geographic origin of beech scale, Cryptococcus fagisuga (Hemiptera: Eriococcidae), an invasive pest in North America". Biological Control. 39 (1): 9–18. doi:10.1016/j.biocontrol.2006.04.009.
  7. Gora, Vincenz; König, Jürgen; Lunderstädt, Jörg (1996). "Population dynamics of beech scale (Cryptococcus fagisuga) (Coccina, Pseudococcidae) related to physiological defence reactions of attacked beech trees (Fagus sylvatica)". Chemoecology. 7 (2): 112–20. doi:10.1007/BF01239488. S2CID   36587090.
  8. Houston, David R. (1998). "Beech bark disease". In Britton, Kerry O. (ed.). Exotic pests of eastern forests: Proceedings of a conference. Nashville, TN: Tennessee Exotic Plant Pest Council: In cooperation with U.S.Department of Agriculture, Forest Service. pp. 29–41. OCLC   45085218.
  9. Forest Encyclopedia Network [ full citation needed ]