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.
The San Jose scale or China scale,, is a hemipterous insect in the family Diaspididae. It is an agricultural pest as it causes damage and crop losses to many fruit crops. In 1914, this species became the first documented case of insecticide resistance.
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.
Eriococcidae is a family of scale insects in the order Hemiptera. They are commonly known as felt scales or eriococcids. As of 2023, there are 109 genera and 681 species. Each species is usually specific to a different plant host, or closely related group of hosts.
Aulacaspis yasumatsui, or cycad aulacaspis scale (CAS), is a scale insect species in the genus Aulacaspis that feeds on cycad species such as Cycas revoluta or Dioon purpusii. Other common names include the cycad scale, the sago palm scale, and the Asian cycad scale. This is a serious pest of cycads which can kill its host plant.
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.
Fiorinia is a genus of armored scale insects with around 70 species. The species are widely distributed around the world. However, the large majority of them are found in southern Asia. They infest woody plants like forest or crop trees, palm trees and shrubs. Several species are invasive and these are mainly polyphagous species which have spread with the trade of ornamentals. For example, 7 species have been introduced into North America.
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.
Euthyrhynchus floridanus, the Florida predatory stink bug, is a species of carnivorous shield bug in the family Pentatomidae, the only species in the genus Euthyrhynchus. It is native to the hottest parts of the southeastern United States and is considered beneficial because its diet includes many species of pest insects.
Saissetia coffeae, known generally as hemispherical scale, is a species of soft scale insect in the family Coccidae. Other common names include the helmet scale and coffee brown scale.
Pseudaulacaspis pentagona, the white peach scale or mulberry scale, is a species of armoured scale insect in the family Diaspididae. This scale infests over 100 different genera of plants including many fruit trees and ornamentals.
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.
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.
Aeolesthes sarta, commonly known as the city longhorn beetle, is a species of beetle in the family Cerambycidae, the longhorn beetles.
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.
Selenaspidus articulatus is an armoured scale insect in the family Diaspididae, commonly known as the West Indian red scale. It is a polyphagous species found in tropical and subtropical regions around the world as a pest species of Citrus and other fruit and ornamental trees.
Fiorinia theae, the tea scale, is a polyphagous scale insect which is native to Asia and has been introduced into the Americas. It is widely distributed on both continents, especially in warmer regions. Apart from tea, the host plants include a range of trees and shrubs, both ornamentals and crops. For example, other Camellia species, Citrus or Ilex (holly) species are part of the host range. Infested plants turn yellow and might die after heavy infestation.
Fiorinia fioriniae is a highly polyphagous scale insect and widely distributed around the world, being found in Asia, Australia/Pacific, Africa, Europe and the Americas. Its vernacular names include fiorinia scale, palm fiorinia scale, and avocado scale. It can cause significant damage to palms, avocado as well as other fruit and ornamental trees. It has been cited as one of two species of Fiorinia in a list of 43 "principle armoured scale pests of the world".
Fiorinia phantasma, the phantasma scale, is an invasive and polyphagous scale insect, apparently native to parts of south-eastern Asia and some Pacific islands. It has invaded other parts of the Pacific, Asia, the Indian Ocean, Europe and the Americas, spreading with the trade of ornamental plants. It has caused serious outbreaks on palm trees, but also infests various other woody plants, including a number of ornamentals and fruit trees like mango or lychee.
