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 silverleaf whitefly is one of several species of whitefly that are currently important agricultural pests. A review in 2011 concluded that the silverleaf whitefly is actually a species complex containing at least 40 morphologically indistinguishable 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.
Maconellicoccus hirsutus, is a pest of many plants, trees, and shrubs. It infests hibiscus, citrus, coffee, sugar cane, annonas, plums, guava, mango, okra, sorrel, teak, mora, pigeon pea, peanut, grapevine, maize, asparagus, chrysanthemum, beans, cotton, soybean, cocoa, and many other plants. The pest forms colonies on the host plant, and if left undisturbed, the colonies will grow into large masses of white waxy coverings on branches, fruiting structures, leaves, and even whole plants, including large trees.
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.
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.
Cryptococcus fagisuga, commonly known as the beech scale or woolly beech scale, is a felted scale insect in the superfamily Coccoidea that infests beech trees of the genus Fagus. It is associated with the transmission of beech bark disease because the puncture holes it makes in the bark allow entry of pathogenic fungi which have been identified as Nectria coccinea var. faginata and sometimes Nectria galligena.
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.
The spotted lanternfly is a planthopper indigenous to parts of China and Vietnam. It has spread invasively to Japan, South Korea, and the United States. Its preferred host is tree of heaven, but it infests crops including soybean, grapes, stone fruits, and Malus spp. In its native habitat, L. delicatula populations are regulated by parasitic wasps.
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.
Xylosandrus compactus is a species of ambrosia beetle. Common names for this beetle include black twig borer, black coffee borer, black coffee twig borer and tea stem borer. The adult beetle is dark brown or black and inconspicuous; it bores into a twig of a host plant and lays its eggs, and the larvae create further tunnels through the plant tissues. These beetles are agricultural pests that damage the shoots of such crops as coffee, tea, cocoa and avocado.
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.
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.
Ceroplastes rubens, known generally as the red wax scale or pink wax scale, is a species of soft scale insect in the family Coccidae. It is native to Australia but has been introduced to other countries, including New Caledonia, Japan, China, Poland and the United States.
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.
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.
