Aonidiella aurantii

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California red scale
Aonidiella aurantii.JPG
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Suborder: Sternorrhyncha
Family: Diaspididae
Genus: Aonidiella
Species:
A. aurantii
Binomial name
Aonidiella aurantii
Synonyms
  • Aspidiotus aurantii
  • Chrysomphalus aurantii

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 [1] 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. [2]

Contents

Description

Specimen Aonidiella aurantii specimen.jpg
Specimen

The female scale insect has a circular, brownish-red cover about 1.8 millimetres in diameter. It is firmly attached to the surface when the female is moulting or reproducing. The insect itself is visible through the cover and has an oval body which becomes kidney-shaped at the last instar stage. The female molts twice, exuding the material from which the cover is formed and developing a concentric ring in the center each time. [3] There is a characteristic whitish coating on the underside of the body which separates it from the host plant. [4] The female is viviparous with the eggs hatching internally. [5] She produces 100 to 150 young altogether and live nymphs or crawlers emerge from under their mother's cover at the rate of two to three per day. When they first hatch the nymphs are a yellowish color and search for a suitable place to settle in depressions on twigs, leaves or fruits. They then start feeding by inserting their mouthparts deep into the plant tissue and sucking sap from the parenchyma cells. The saliva they inject is very toxic to the leaves, twigs, branches and fruit of citrus trees. [6] They soon begin to develop their own round, waxy covers. [3]

The male scale insect develops similarly until after the second moult when it becomes oval and darker than the female, measuring about one millimetre in diameter with an eccentric cover. The adult male is a small, yellowish two-winged insect that emerges from under its elongated cover after four molts. It lives for about 6 hours and its sole purpose is to mate. [4] It locates unmated females by detecting the pheromones they release. [7]

Damage and control

Red scale is potentially a severe pest of citrus in California, Australia, New Zealand, Mexico, Chile, Argentina, Brazil, Israel, the eastern Mediterranean islands, [8] and South Africa. [6]

Although citrus is the main crop attacked by red scale, it can also be found on species from at least seventy-seven plant families [9] and has been successfully reared in the laboratory on potato tubers and pumpkin. [10] Scale insects of all ages feed by sucking sap. They are found on all parts of the plant but are most noticeable on the fruit. Heavy infestations may cause discoloration, shoot distortion and leaf drop. The fruit may become pitted and unmarketable. The tree's bark may split and the twigs and branches may die back and this sometimes results in the death of the tree. Chemical control is difficult because the insects are protected by their hard waxy covers. They are also becoming resistant to many insecticides and indiscriminate use of pesticides has adverse effects on their natural predators. [3]

Some ant species can increase infestations of red scale indirectly. By patrolling the branches in search of honeydew from soft scales, cottony cushion scale, mealybugs and aphids, they deter predators and parasitoids and thus enable red scale to flourish unmolested. [11] The only mobile stage of red scale is the first instar crawler. It can move about a metre but may also be dispersed to other plants by wind, flying insects and birds as well as human activities. [12]

Other crops that suffer economic damage from attack by red scale include papaya (Carica papaya) in Taiwan, [13] guava (Psidium guajava) in India [14] and olives in California and countries around the Mediterranean, with serious damage being caused to olives in Morocco. [15]

Natural enemies of red scale vary in the different parts of the world in which it is found. Parasitoids include Aphelinus africanus , several species of Aphytis , Comperiella bifasciata , species of Encarsia , Habrolepis rouxi and Signiphora fax . [5] Predators include Aleurodothrips fasciapennis , several species of Chilocorus , Cybocephalus micans , Cryptolaemus montrouzieri , Hemisarcoptes malus and Rhyzobius lophanthae . [5]

In California, several predators feed on red scale including the lady beetles, Rhyzobius lophanthae , Chilocorus orbus and Chiliocorus cacti . The naturally occurring parasitic wasps, Aphytis melinus , Aphytis lingnanensis and Comperiella bifasciata also play a part in controlling red scale on citrus but their ability to do so depends on the selective use of insecticides for other pests. Careful monitoring of the host plants will indicate whether release of captive-bred Aphytis melinus is necessary and the use of pesticides should be minimized before this is done. Ants, especially the Argentine ant, Linepithema humile , and the native gray ant should also be controlled as they disrupt the predation of the scale insects by the wasp. [3]

In Australia, the parasitic wasp Aphytis lingnanensis is used for biological pest control. It is usually released annually as, although the wasps may build up naturally without being released, the life cycle is not well synchronized with the pest and significant populations of scale insect may build up before many wasps are available. [16]

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>Rhyzobius</i> Genus of beetles

Rhyzobius is a genus in the lady beetle family (Coccinellidae). It belongs to tribe Coccidulini of subfamily Coccidulinae, which is sometimes subsumed in the Coccinellinae as a tribe with the Coccidulini downranked to subtribe.

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

Diaspididae is the largest family of scale insects with over 2650 described species in around 400 genera. As with all scale insects, the female produces a waxy protective scale beneath which it feeds on its host plant. Diaspidid scales are far more substantial than those of most other families, incorporating the exuviae from the first two nymphal instars and sometimes faecal matter and fragments of the host plant. These can be complex and extremely waterproof structures rather resembling a suit of armor. For this reason these insects are commonly referred to as armored scale insects. As it is so robust and firmly attached to the host plant, the scale often persists long after the insect has died.

<i>Technomyrmex albipes</i> Species of ant

Technomyrmex albipes, commonly known as the white-footed ant, is a species of ant first described in 1861 from Sulawesi, Indonesia by the British entomologist Frederick Smith. Invasive pest ants in Florida, previously identified as T. albipes, have now been separated as Technomyrmex difficilis, both forming part of a species complex with a worldwide distribution.

Aphytis melinus is an internal parasite of the California red scale, Aonidiella aurantii, which is a pest of citrus in California and elsewhere. This wasp drums its antennae against the scale insect to find out if it is healthy, if it is already parasitized, how large it is, etc., to decide how to use this prey. It has four choices : leave the scale to keep searching, feed directly on the scale, use the scale as a host for a male A. melinus, or use the scale for a female A. melinus.

Aphytis is a genus of chalcid wasps in the family Aphelinidae. There are about 130 species.

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

Lepidosaphes beckii also known as purple scale, mussel scale, citrus mussel scale, orange scale, comma scale and mussel purple scale is a scale insect that is a pest of Citrus trees. The small insects attach themselves to leaves, fruits and small branches and cause injury by sucking the tree's sap.

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

Aonidiella orientalis is a species of insect in the family Diaspididae, the armored scale insects. It is known commonly as the Oriental yellow scale. It is an agricultural pest on a wide variety of crop plants.

<i>Comperiella bifasciata</i> Species of wasp

Comperiella bifasciata is a parasitic wasp species in the genus Comperiella in the family Encyrtidae. It is used in biological control of California red scale and yellow scale of citrus.

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.

Rhyzobius lophanthae, commonly known as the purple scale predator or the scale-eating ladybird, is a species of ladybird native to Queensland and Southern Australia. It was introduced into the United States in the 1890s and has since spread over the southern half of the country.

Pseudotheraptus wayi, the coconut bug, is a species of leaf-footed bug in the family Coreidae. It is a pest of coconut in East Africa.

Hemiberlesia lataniae, the latania or palm scale, is a species of armored scale insect in the family Diaspididae. It was first described by the French entomologist Victor Antoine Signoret in 1869 using Latania lontaroides, a species of palm tree endemic to Réunion as its host; since then, it has been found on avocado trees growing in South Africa, Australia, Israel, the United States, and on a range of other plants in many parts of the world.

<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.

Encarsia perniciosi is a tiny parasitic wasp, a parasitoid of the California red scale and the San Jose scale on citrus in California.

Chilocorus orbus is a species of lady beetle in the family Coccinellidae. It is native to North America. It is a black, domed beetle with two large red spots and is commonly called the twice-stabbed lady beetle or the two-stabbed lady beetle. Both adults and larvae feed on scale insects.

<i>Chilocorus cacti</i> Species of beetle

Chilocorus cacti, known generally as the cactus lady beetle or the twice-stabbed cactus lady beetle, is a species of lady beetle in the family Coccinellidae. It is native to the Caribbean region, North America, Central America, and South America. The adults and larvae feed on scale insects and attempts have been made to use it for biological pest control.

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.

References

  1. ↑ Longo, S., Marotta, S., Pellizzari, G., Russo, A. and A. Tranfaglia, 1995. "An annotated list of the scale insects (Homoptera: Coccoidea) of Italy". Israel Journal of Entomology 29: 113–130.
  2. ↑ Robert F. Luck; Mark Hoddle. "California Red Scale". Center for Invasive Species Research, University of California, Riverside. Retrieved February 26, 2014.
  3. 1 2 3 4 "California Red Scale and Yellow Scale". UC Pest Management Guidelines. Agriculture and Natural Resources, University of California. June 2013. Retrieved February 26, 2014.
  4. 1 2 "California red scale". HYPPZ. Retrieved February 26, 2014.
  5. 1 2 3 Parry-Jones, E., 1936. "Bionomics and ecology of red scale in Southern Rhodesia". Publication Mazoe Citrus Experimental Station 5: 11–52.
  6. 1 2 Bedford, E. C. G., 1998. "Red scale Aonidiella auranii (Maskell)". In: E. C. G. Bedford, M.A. Van den Berg and E. A. De Villiers (eds.), Citrus pests in the Republic of South Africa. Dynamic Ad., Nelspruit, South Africa: 132–134.
  7. ↑ Roelofs, W. L., Gieselmann, M. J., Carde, A. M., Tashiro, H., Moreno, D. S., Henrick, C. A. and R. J. Anderson, 1978. "Identification of the California red scale sex pheromone". Journal of Chemical Ecology 4: 211–224.
  8. ↑ Ebeling, W., 1959. Subtropical Fruit Pests. University of California, Los Angeles. 436 pp.
  9. ↑ Borchsenius, N. S., 1966. A catalogue of the armored scale insects (Diaspidoidea) of the world. (In Russian.) Nauka, Moscow, Leningrad, Russia. 449 pp.
  10. ↑ Li, C. F. and D. X. Liao, 1990. "Methods of mass rearing four citrus scale insects". Chinese Journal of Biological Control 6: 68–70.
  11. ↑ Annecke, D. P., 1958. "Ants and citrus". Citrus Grower 196: 1–3.
  12. ↑ Ebeling, W., 1950. Subtropical entomology. Lithotype Process Co., San Francisco, California. 747 pp.
  13. ↑ Chua, T. H. and B. J. Wood, 1990. 3.9.2 "Other tropical fruit trees and shrubs". In: D. Rosen (ed.), Armoured scale insects, their biology, natural enemies and control. Vol. 4B. World Crop Pests. Elsevier, Amsterdam, the Netherlands: 543–552.
  14. ↑ Hayes, W. B., 1970. Fruit growing in India. Third edition. Kitabistan, Allahabad. 512 pp.
  15. ↑ Argyriou, L. C., 1990. "Olive". In: D. Rosen (ed.), Armoured scale insects, their biology, natural enemies and control. Vol. 4B. World Crop Pests. Elsevier, Amsterdam, the Netherlands: 579–583.
  16. ↑ "Aphytis". Bugs for Bugs. Archived from the original on May 10, 2013. Retrieved February 26, 2014.
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