| Yellow scale | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hemiptera |
| Suborder: | Sternorrhyncha |
| Family: | Diaspididae |
| Genus: | Aonidiella |
| Species: | A. citrina |
| Binomial name | |
| Aonidiella citrina Coquillett, 1891 [1] | |
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.
Armoured scales are so-called because they are covered by a hard, plate-like structure, the scale. The adult female yellow scale insect is concealed under a thin, pale circular scale through which its yellowish body colour can be seen. The female is legless and remains in the same location permanently, anchored to the surface. The male is a similar colour and has an elongate oval scale. The exuviae (shed nymphal skins) are located near the centre in the female scale but are near one end in the male insect. When the adult male emerges from under its scale after four moults, it has limbs and a single pair of wings and is able to fly rather weakly; it lives for only a few hours, and its sole purpose is to find and mate with a female. [2] [3]
The adult female scale insect is viviparous, the eggs hatching internally, and produces up to 150 young at the rate of two or three per day. The first-stage larva is mobile and is known as a crawler; it emerges from under the mother's scale and disperses to other parts of the plant; it may be blown by the wind or transported elsewhere by animals and is the only mobile life stage except for the adult male. When it has found a depression or other suitable location, it pierce the host plant with its mouthparts and sucks sap. The female nymph moults twice as it develops while the male moults four times. [3]
Yellow scale has a widespread distribution in Asia, the Mediterranean area, Africa and South America, and is a serious pest of citrus in the southern United States, China, Japan, India, Iran and Australia. [1] When it first appeared in California it was thought to be a yellow variant of red scale (Aonidiella aurantii) because the two are so similar in morphology. However, later various microscopic differences between them were noticed. Yellow scale affects fewer host plants than does red scale, [4] and it is more susceptible to insecticides and biological pest control. [3]
Yellow scale insects seldom feed on the woody parts of plants, concentrating on the leaves and fruits. It is a less serious pest of citrus than red scale because its effects are more cosmetic, and because it is easier to control. [4] Heavy infestations of the insect can cause yellowing of the leaves, leaf fall, dieback of twigs and branches, or even tree death. Fruits may be disfigured and attain lower prices. In California, many populations of both red and yellow scale have become resistant to some of the most commonly used pesticides, but biological control using chalcid wasp parasitoids is very effective; Aphytis melinus and Aphytis lingnanensis are used in mild coastal areas and Comperiella bifasciata in inland areas such as the San Joaquin Valley. [2]
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.
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.
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.
Icerya purchasi 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.
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.
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.
Diaphorina citri, the Asian citrus psyllid, is a sap-sucking, hemipteran bug in the family Psyllidae. It is one of two confirmed vectors of citrus greening disease. It has a wide distribution in southern Asia and has spread to other citrus growing regions.
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.
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.
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.
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.
Dysdercus koenigii is a species of true bug in the family Pyrrhocoridae, commonly known as the red cotton stainer. It is a serious pest of cotton crops, the adults and older nymphs feeding on the emerging bolls and the cotton seeds as they mature, transmitting cotton staining fungi as they do so.
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.
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.
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.
Saissetia oleae is a scale insect in the family Coccidae. It is considered one of the three main phytophagous parasites of the olive tree, together with the olive fruit fly and the olive moth. Although it is a common parasite which occurs most often in olive trees, it is a polyphagous species, also attacking citrus trees as well as various ornamental shrubs such as oleanders, pittosporums, sago palm, and euonymus.
Protopulvinaria pyriformis, commonly known as the pyriform scale, is a species of soft scale insect in the family Coccidae. It is a pest of avocado and is found in many countries around the world where avocados grow.
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.
Carulaspis minima is an armoured scale insect, in the subtribe Diaspidina of the family Diaspididae, and is commonly known as the minute cypress scale. It was first described in 1869 by the French entomologist Victor Antoine Signoret. It feeds on evergreen conifers in the families Cephalotaxaceae, Cupressaceae and Taxodiaceae.
Planococcus ficus, commonly known as the vine mealybug, is a species of mealybug, belonging to the family Pseudococcidae, native to tropical and subtropical regions. The vine mealybug is found in Europe, Northern Africa, Southern Africa, the Americas, and the Middle East. The vine mealybug is invasive to weedy plants in many different regions of the world.
| Authority control databases: National |
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