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Associations

provided by BioImages, the virtual fieldguide, UK
Foodplant / sap sucker
Icerya purchasi sucks sap of live Citrus
Other: major host/prey

Foodplant / sap sucker
Icerya purchasi sucks sap of live Cytisus
Other: major host/prey

Foodplant / sap sucker
Icerya purchasi sucks sap of live Rosa
Other: major host/prey

In Great Britain and/or Ireland:
Foodplant / sap sucker
Icerya purchasi sucks sap of live Acacia
Other: major host/prey

Foodplant / sap sucker
Icerya purchasi sucks sap of live Mimosa
Other: major host/prey

Foodplant / sap sucker
Icerya purchasi sucks sap of live Broadleaved trees and shrubs

Foodplant / sap sucker
Icerya purchasi sucks sap of live Laurus nobilis

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Brief Summary

provided by EOL authors
The cottony cushion scale (Icerya purchasi) is a homopteran pest native to Australia. Its Australian host plant is kangaroo acacia, but it is found on a wide variety of woody plant species. It is especially common on Citrus and Pittosporum (cheesewoods). Icerya purchasi is notable in that it was a pest overcome by one of the first major successes of effective biological control. In 1886 or 1887, the cottony cushion scale made its way into California on imported acacia plants. Not long after this, I. purchasi became a severe threat to the Californian citrus industry, which was just starting out at that time. In order to manage the overwhelming I. purchasi populations, C. V. Riley, later the head of the USDA’s Division of Entomology, imported the vedalia ladybeetle (Rodolia cardinalis), a natural enemy from Australia. The ladybug predators very effective and quickly controlled I. purchasi populations, saving the California citrus groves. At about the same time as it reached California, Icerya purchasi was also introduced into New Zealand and South Africa. It is now found world-wide, especially where citrus grows. Covered with fluffy-looking white or yellow wax, the adult insects are large (up to 10 mm long) and usually have the conspicuous feature of a large egg sac (2-3 times the scale’s body length) with ridges running the length of it. Icerya purchasi are mostly hermaphroditic and finding males in a population is rare. Unlike most scale insects which permanently settle at later stages, cottony cushion scales are somewhat mobile at all stages of development, yet their dispersal stage is still the early instar (crawler) stage, when they can be carried by wind, crawling or hitchhiking on other animals to new host plants. Especially at the early nymph stages, this pest can badly damage citrus trees and reduce fruit production by sucking significant quantities of plant juices from veins on the leaf midrib and also from small twigs of the plant. Because they also produce a honeydew, cottony cushion scales make plants susceptible to sooty molds, which inhibit photosynthesis and further damage the plant. The vedalia ladybeetle and the (also introduced) parasitic fly Cryptochaetum iceryae are very abundant and specific attackers of the cottony cushion scale. With these insects around, I. purchasi is considered only a minor pest of citrus orchards and no chemical control is needed or recommended, as pesticides are often toxic to these predators. A means of further controlling I. purchasi populations is to control their attendant ants, which protect the scales from predators in exchange for eating honeydew. Ant populations can often be reduced using tanglefoot or ant baiting. (CABI, 2011; Grafton-Cardwell 2011; Hamon and Fasulo 2005; Wikipedia 2011)
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Icerya purchasi

provided by wikipedia EN

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]

Life cycle

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

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

Rodolia cardinalis 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]

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. ^ a b c 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. ^ a b "Cottony Cushion Scale Management Guidelines--UC IPM". ipm.ucanr.edu.
General

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Wikipedia authors and editors
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visit source
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wikipedia EN

Icerya purchasi: Brief Summary

provided by wikipedia EN

Icerya purchasi (common name: cottony cushion scale) is a scale insect that feeds on more than 80 families of woody plants, 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". It is now found worldwide where citrus crops are grown. The cottony cushion scale originates from Australia.

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cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
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wikipedia EN