Icerya purchasi

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Icerya purchasi
Icerya-purchasi.jpg
Icerya purchasi female
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Suborder: Sternorrhyncha
Family: Monophlebidae
Genus: Icerya
Species:
I. purchasi
Binomial name
Icerya purchasi
Maskell, 1878
Synonyms
  • Icerya purchasi crawii Cockerell, 1897
  • Icerya purchasi maskelli Cockerell, 1897
  • Icerya purchasi citriperda Hempel, 1920

Icerya purchasi (common name: cottony cushion scale) is a scale insect that feeds on more than 80 families of woody plants, [1] most notably on Citrus and Pittosporum . Originally described in 1878 from specimens collected in New Zealand as pests of kangaroo acacia and named by W.M. Maskell "after the Rev. Dr. Purchas who, [he] believe[d], first found it", [2] it is now found worldwide where citrus crops are grown. The cottony cushion scale originates from Australia. [3]

Contents

Life cycle

Small colony Icerya purchasi 1435060.jpg
Small colony

This scale infests twigs and branches. The mature hermaphrodite is oval in shape, reddish-brown with black hairs, 5 mm long. When mature, the insect remains stationary, attaches itself to the plant by waxy secretions, and produces a white egg sac in grooves, by extrusion, in the body which encases hundreds of red eggs. The egg sac will grow to be two to three times as long as the body. Newly hatched nymphs are the primary dispersal stage, with dispersion known to occur by wind and by crawling. Early stage nymphs feed from the midrib veins of leaves and small twigs, and do the bulk of the damage. At each molt, they leave at the old feeding point the former skin and the waxy secretions in which they had covered themselves and from which their common name is derived. Unlike many other scale insects, they retain legs and a limited mobility in all life stages. Older nymphs migrate to larger twigs and eventually as adults to branches and the trunk. Their life cycle is highly temperature-dependent, as the length of time in each stage of life is longer in cold temperatures than high temperatures.

In addition to the direct damage from sap sucking, the insects also secrete honeydew, on which sooty mold often grows and causes further damage to the host plant. Some ants will also consume this honeydew.

Reproduction

Illustration of a male Icerya purchasi male.jpg
Illustration of a male

Males are rare in hermaphroditic species of Icerya. Males are haploid while females are diploid. Females have an ovitestis that is capable of producing both sperm and oocytes which fertilize internally to produce diploid offspring (females) through a form of hermaphroditism. The cells of the ovitestis are haploid and are derived from excess sperm during matings with males. This has been termed as 'parasitic tissue' and theoretical studies have examined this as a form of sexual conflict and have examined the possible fates and fitness consequences since females can produce daughters by mating with males or using their parasitic male cell lines. Females that lack ovitestes may preferentially invest in producing sons while females with parasitic tissue should prefer to pass on the genetic material through daughters. [4]

True males are uncommon to rare overall, and in many infestations are not present. Pure females are unknown. Self-fertilization by a hermaphrodite will produce only hermaphrodites. Matings of a male and hermaphrodite will produce both males and hermaphrodites. [5]

Biological control

Novus cardinalis, known as the Vedalia beetle, feeding on cottony cushion scale Rodolia cardinalis USDA.jpg
Novus cardinalis , known as the Vedalia beetle, feeding on cottony cushion scale

Icerya purchasi is important as one of the first major successes of biological control. Importations of the vedalia ladybird ( Novius cardinalis ) in 1888-1889 by C. V. Riley, later head of the USDA's Division of Entomology, resulted in swift reductions of I. purchasi populations, saving the burgeoning Californian citrus industry from this destructive pest. [6]

A second biological control, the parasitic fly Cryptochetum iceryae has also been introduced to California as an additional control vector at around the same time. [6]

While there is an apparent rivalry between the 2 natural enemies of Icerya purchasi, the competition does not affect the efficacy of the control measures when both the beetle and the fly are introduced. [6] Biological control remains the most effective measure to manage Icerya purchasi infestations [7] Use of insecticides as control is recommended only if no biological control species is present. Imidacloprid is especially contraindicated, since it has no effect on this species, but is very toxic to Novius cardinalis. [7]

Related Research Articles

<span class="mw-page-title-main">Biological pest control</span> Controlling pests using other organisms

Biological control or biocontrol is a method of controlling pests, whether pest animals such as insects and mites, weeds, or pathogens affecting animals or plants by using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also involves an active human management role. It can be an important component of integrated pest management (IPM) programs.

<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.

<i>Aonidiella aurantii</i> Species of true bug

Aonidiella aurantii or red scale is an armored scale insect and a major pest of citrus. It is thought to be a native of South China but has been widely dispersed by the agency of man through the movement of infected plant material. In the United States it is known as California red scale. It was first found in California between 1868 and 1875, apparently brought there on planting material imported from Australia.

<i>Icerya</i> Genus of true bugs

Icerya is a genus of scale insects in the family Monophlebidae. It is named after physician-naturalist Dr. Edmond Icery of British Mauritius.

<i>Stratiolaelaps scimitus</i> Species of mite

Stratiolaelaps scimitus is a small (0.5 mm) light brown mite that lives in the top 12 inch (13 mm) layer of soil. As a natural predator of fungus gnat pupae and of the snail parasite Riccardoella limacum it is used by gardeners and snail breeders for biological pest control. Stratiolaelaps scimitus is also commonly used by reptile, amphibian and invertebrate keepers as a preventative or reactive measure against grain mites and reptile mites. Whereas most mite treatments are based on synthetic chemicals, predatory mites are used as a biological method of preventing and curing mite infestations.

<i>Pseudococcus viburni</i> Species of true bug

Pseudococcus viburni is a close relative of the grape mealybug and a pest of the vineyards around the world.

<span class="mw-page-title-main">William Miles Maskell</span> New Zealand farmer, politician and entomologist

William Miles Maskell was a New Zealand farmer, politician and entomologist.

<span class="mw-page-title-main">Albert Koebele</span> American entomologist

Albert Koebele was an economic entomologist and a pioneer in the use of biological controls to manage insect pests.

<i>Novius cardinalis</i> Species of beetle

Novius cardinalis is a species of ladybird beetle native to Australia. It was formerly placed in the genus Rodolia, but that genus was synonymized under the genus Novius in 2020.

<i>Aleurocanthus woglumi</i> Citrus pest from India, now worldwide

Aleurocanthus woglumi is a species of whitefly in the family Aleyrodidae. It is a pest of citrus crops, and is commonly known as the citrus blackfly because of its slate-blue colour. It originated in Asia, but has spread to other parts of the world. The parasitic wasps, Encarsia perplexa and Amitus hesperidum can help control the pest.

<i>Cryptococcus fagisuga</i> Species of true bug

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 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.

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

Monophlebidae is a family of scale insects commonly known as the giant scales or monophlebids. They occur in most parts of the world but more genera are found in the tropics than elsewhere.

<i>Planococcus citri</i> Species of true bug

Planococcus citri, commonly known as the citrus mealybug, is a species of mealybugs native to Asia. It has been introduced to the rest of the world, including Europe, the Americas, and Oceania, as an agricultural pest. It is associated with citrus, but it attacks a wide range of crop plants, ornamental plants, and wild flora.

<i>Novius</i> (beetle) Genus of beetles

Novius is a genus of ladybird beetles belonging to the family Coccinellidae, and the sole member of the tribe Noviini. The genus as presently defined contains over 70 species, most of which were formerly placed in the genera Rodolia and Anovia, but after decades of debate, both of these genera are now considered to be junior synonyms of Novius.

<span class="mw-page-title-main">F. S. Crawford</span> Australian photographer and agricultural expert

Frazer Smith Crawford was a photographer in the colony of South Australia, founding manager of the Adelaide Photographic Company, then photolithographer for the Government of South Australia. In a seemingly unrelated sphere, Crawford came to be recognised as an authority on agricultural pests and diseases, particularly known for identifying and exploiting naturally occurring predators of plant pests.

Aonidiella citrina or yellow scale is an armored scale insect from the family Diaspididae. It feeds by sucking sap from plants in a number of plant families, but is mostly known for being a pest of citrus.

<i>Cryptochetum iceryae</i> Species of fly

Cryptochetum iceryae, the cottony cushion scale parasite, is a species of scale parasite fly in the family Cryptochetidae. Originating in Australia, it was deliberately introduced to California in the 1880s in an attempt to control cottony cushion scale, and has also been introduced to Israel and South America. In 2019, the species was discovered in the United Kingdom for the first time, having been identified in the wildlife garden at the Natural History Museum.

<i>Novius iceryae</i> Species of beetle

Novius iceryae is a species of ladybird beetle native to Afrotropical realm, and was described from South Africa. It is also found in Senegal. In 1880, Novius iceryae was used to successfully control cottony cushion scale, Icerya purchasi in South Africa. It was later introduced in New Zealand for the management of cottony cushion scale. This and related species were formerly classified in the genus Rodolia.

Metaphycus helvolus is a species of parasitic wasp in the family Encyrtidae native to South Africa. It is a parasitoid of soft scale insects and has been used in their biological control in California and Australia.

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

Quadraspidiotus 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.

References

  1. García Morales, M.; Denno, B.D.; Miller, D.R.; Miller, G.L.; Ben-Dov, Y.; Hardy, N.B. (2016). "Icerya purchasi". Database: The Journal of Biological Databases and Curation. 2016. doi:10.1093/database/bav118. PMC   4747323 . PMID   26861659 . Retrieved 2021-05-22.
  2. Maskell, W.M. (1879) [1878]. "On some Coccidae in New Zealand". Transactions and Proceedings of the New Zealand Institute. 11: 187–228.
  3. Nair, K. S. S. (2007). Tropical Forest Insect Pests: Ecology, Impact, and Management. Cambridge University Press. ISBN   9781139464857.
  4. Laura, Andy; Ross, Gardner (2011). "The Evolution of Hermaphroditism by an Infectious Male-Derived Cell Lineage: An Inclusive-Fitness Analysis" (PDF). The American Naturalist. 178 (2): 191–201. doi:10.1086/660823. hdl: 11370/c2d17516-c096-4e53-80a1-d79b3aab10b3 . PMID   21750383. S2CID   15361433.
  5. Gardner, Andy; Ross, Laura (2011). "The Evolution of Hermaphroditism by an Infectious Male-Derived Cell Lineage: An Inclusive-Fitness Analysis". The American Naturalist. 178 (2): 191–201. doi:10.1086/660823. hdl: 11370/c2d17516-c096-4e53-80a1-d79b3aab10b3 . PMID   21750383. S2CID   15361433.
  6. 1 2 3 Quezada, José R.; DeBach, Paul (April 1973). "Bioecological and population studies of the cottony-cushion scale, Icerya purchasi Mask., and its natural enemies, Rodolia cardinalis Mul. and Cryptochaetum iceryae Will., in southern California". Hilgardia. 41 (20): 631–688. doi: 10.3733/hilg.v41n20p631 .
  7. 1 2 "Cottony Cushion Scale Management Guidelines--UC IPM". ipm.ucanr.edu.

Further reading