''Aonidiella orientalis'' is a species of insect in the family

Diaspididae 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 mo ...

, the armored scale insects. It is known commonly as the Oriental yellow scale.''Aonidiella orientalis'' (Oriental yellow scale).
Invasive Species Compendium. CABI. It is an agricultural pest on a wide variety of crop plants.

Description

This is a

scale insect Scale insects are small insects of the Order (biology), order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient g ...

, a tiny insect which is most easily identified by the female, which attaches itself to a host plant, loses its legs, and remains stationary covered by a somewhat rounded scale-like shield of wax. In this species, the female forms a flat, circular scale which is white, brown, or yellow in color. It is up to 2.6 millimeters long.''Aonidiella orientalis'' (Oriental scale).
Arthropods of Economic Importance. World Biodiversity Database. ETI Bioinformatics. The insect within is no more than 1.4 millimeters long. The winged male of this species also produces a scale.

Distribution

This species is likely native to

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

. It can be found nearly worldwide today because it has been introduced to many areas with shipments of plants and then began a slow spread. It is common in many tropical and subtropical areas, and it can survive in

greenhouse A greenhouse is a structure that is designed to regulate the temperature and humidity of the environment inside. There are different types of greenhouses, but they all have large areas covered with transparent materials that let sunlight pass an ...

s in cooler regions. It is not known from Europe. Some ports check for this and other scales in

quarantine A quarantine is a restriction on the movement of people, animals, and goods which is intended to prevent the spread of disease or pests. It is often used in connection to disease and illness, preventing the movement of those who may have bee ...

d plant shipments.

Biology

The female attaches to the surface of a plant, forms a waxy shield, and lays eggs beneath it. They are often

viviparous In animals, viviparity is development of the embryo inside the body of the mother, with the maternal circulation providing for the metabolic needs of the embryo's development, until the mother gives birth to a fully or partially developed juve ...

, producing live young instead of laying eggs. The

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e emerge and leave the shield; at this point they are called "crawlers". They roam the plant, feeding on sap by inserting their stylets. Males reach the adult stage at about 19 days. Females reach adulthood and yield the next generation of larvae at about 44 days. Males have wings but no mouthparts, and they do not feed. There are about three to five generations per year, depending on conditions.

Impact

This species is highly polyphagous: it can feed on a wide variety of plant taxa. It has been found on most every kind of plant except

conifer Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

s. It is problematic in many kinds of plant crops, including fruits, vegetables, herbs, medicinal plants, fiber plants, oil plants, and ornamental plants. Crops affected include sisal hemp,

tea Tea is an aromatic beverage prepared by pouring hot or boiling water over cured or fresh leaves of '' Camellia sinensis'', an evergreen shrub native to East Asia which probably originated in the borderlands of south-western China and nor ...

cotton Cotton (), first recorded in ancient India, is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure ...

, mastic,

oil palms ''Elaeis'' () is a genus of palms, called oil palms, containing two species, native to Africa and the Americas. They are used in commercial agriculture in the production of palm oil. Description Mature palms are single-stemmed, and can grow ...

neem ''Azadirachta indica'', commonly known as neem, margosa, nimtree or Indian lilac, is a tree in the mahogany family Meliaceae. It is one of the two species in the genus '' Azadirachta''. It is native to the Indian subcontinent and to parts of S ...

, and many foods and flowers. The insect damages the plant by sucking sap, weakening it. The physical damage includes discoloration and deformation of leaves. Flowers and fruits fail to develop. When the insects feed on the fruits they are discolored and warped, reducing their value on the market. Infestations can kill plants, even established trees. Severe impacts can occur in places where the insect is newly introduced. It was first seen in

papaya The papaya (, ), papaw, () or pawpaw () is the plant species ''Carica papaya'', one of the 21 accepted species in the genus '' Carica'' of the family Caricaceae, and also the name of its fruit. It was first domesticated in Mesoamerica, within ...

crops in

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

in 1988, and it rapidly became the most serious pest in the local industry. It was first found on

mango A mango is an edible stone fruit produced by the tropical tree '' Mangifera indica''. It originated from the region between northwestern Myanmar, Bangladesh, and northeastern India. ''M. indica'' has been cultivated in South and Southeast As ...

es in

Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...

in 1980; now it is established in mango groves throughout the surrounding region and is spreading to other local crops, such as

olive The olive, botanical name ''Olea europaea'' ("European olive"), is a species of Subtropics, subtropical evergreen tree in the Family (biology), family Oleaceae. Originating in Anatolia, Asia Minor, it is abundant throughout the Mediterranean ...

and

guava Guava ( ), also known as the 'guava-pear', is a common tropical fruit cultivated in many tropical and subtropical regions. The common guava '' Psidium guajava'' (lemon guava, apple guava) is a small tree in the myrtle family (Myrtaceae), nativ ...

.Ofek, G., et al. (1997)
The control of the oriental red scale, ''Aonidiella orientalis'' Newstead and the California red scale, ''A. aurantii'' (Maskell) (Homoptera: Diaspididae) in mango orchards in Hevel Habsor (Israel).
''Alon Hanotea'', 51(5), 212-218. Some groves are doubly infested, also harboring populations of the related red scale (''Aonidiella aurantii''). It was first found on neem in

Cameroon Cameroon, officially the Republic of Cameroon, is a country in Central Africa. It shares boundaries with Nigeria to the west and north, Chad to the northeast, the Central African Republic to the east, and Equatorial Guinea, Gabon, and the R ...

in 1985 and had spread over one million kilometers by 1998, infesting many economically important trees.

Control

Infested twigs, branches, and shoots can be removed from trees, slowing the spread of the scale.

Pesticide Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...

s have been used, but are less popular now as attention turns to

biological pest control 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 ot ...

. There are many natural enemies of the scale which can be reared and released in infested orchards, reducing scale populations. Natural enemies have been trialed in Queensland's papaya groves. Good results were observed with the

parasitoid wasp Parasitoid wasps are a large group of hymenopteran Superfamily (zoology), superfamilies, with all but the wood wasps (Orussoidea) being in the wasp-waisted Apocrita. As parasitoids, they lay their eggs on or in the bodies of other arthropods, ...

s '' Comperiella lemniscata'' and '' Encarsia citrina''. Other insects, such as the larva of the coconut moth (''Batrachedra arenosella'') and the lady beetles '' Lindores lophanthae'', '' Chilocorus circumdatus'', and '' C. baileyi'' have been helpful in severe infestations.Oriental Scale.
Department of Agriculture and Fisheries, Queensland.

References

{{Authority control Aspidiotina Agricultural pest insects Insects of Asia Insects described in 1894