''Aphis gossypii'' is a tiny insect, an

aphid Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A ...

("greenfly") in the superfamily Aphidoidea in the order Hemiptera. It is a true bug and sucks sap from plants. It is a widely distributed pest of a variety of agricultural crops in the families

Cucurbitaceae The Cucurbitaceae, also called cucurbits or the gourd family, are a plant family consisting of about 965 species in around 95 genera, of which the most important to humans are: *'' Cucurbita'' – squash, pumpkin, zucchini, some gourds *'' La ...

Rutaceae The Rutaceae is a family, commonly known as the rueRUTACEAE
in BoDD – Botanical Der ...

and

Malvaceae Malvaceae, or the mallows, is a family of flowering plants estimated to contain 244 genera with 4225 known species. Well-known members of economic importance include okra, cotton, cacao and durian. There are also some genera containing familiar o ...

. Common names include cotton aphid, melon aphid and melon and cotton aphid.

Distribution

It is not known where this species originated, but it is now found in tropical and temperate regions throughout the world except extreme northern areas. It is common in North and South America, Central Asia, Africa, Australia, Brazil, East Indies, Mexico and Hawaii and in most of Europe. It is cosmopolitan in habitat. It thrives outdoors in southern Europe but survives only under glass in northern Europe. In the former Soviet Union it is found up to 54°N.

Morphology

The wingless female cotton aphid has an ovoid body about two millimetres long in varying shades of green. The legs are yellow, as are the antennae which are three quarters of the length of the body. The apices of the

femora The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with t ...

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...

and tarsi are black. The cylindrical black

siphunculi The cornicle (or siphuncule) is one of a pair of small upright backward-pointing tubes found on the dorsal side of the 5th or 6th abdominal segments of aphids. They are sometimes mistaken for cerci. They are no more than pores in some species. ...

are wide at the base and one fifth of the body length. The winged female has a fusiform body. Its head and thorax are black, the abdomen yellowish-green with black lateral spots and the antennae are longer than those of the

apterous Aptery is the anatomical condition of an animal completely lacking any kind of wings. An animal with this condition is said to be apterous. Most animal species belong to and are phylogenetic descendants of apterous taxa. These groups are said ...

female. The nymphs vary in colour, being shades of green, tan and gray. They often have a dark head, thorax and wing pads and the distal portion of the abdomen is usually dark green. The body appears dull because it is dusted with wax secretions. The oval eggs are yellow when first laid but soon turn glossy black.University of Florida
/ref> In the southern half of the US, as far north as Arkansas, sexual reproduction of the cotton aphid is not important. Females continue to produce offspring without mating so long as the weather is favourable for feeding and growth. Further north, the cotton aphid can be holocyclic and involve two host species, with a broadleaved tree such as

Catalpa ''Catalpa'', commonly called catalpa or catawba, is a genus of flowering plants in the family Bignoniaceae, native to warm temperate and subtropical regions of North America, the Caribbean, and East Asia. Description Most ''Catalpa'' are deci ...

, Rhamnus or

Hibiscus ''Hibiscus'' is a genus of flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. They include all forbs (flowering plants without a woody stem), gras ...

acting as the primary host. In Europe it reproduces exclusively by asexual reproduction and can produce nearly fifty generations a year under favourable conditions. In Russia various wild plants are hosts to the overwintering eggs.AgroAtlas
/ref> Winged forms then migrate to secondary host species in the families

Rosaceae Rosaceae (), the rose family, is a medium-sized family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus ''Rosa''. Among the most species-rich genera are '' Alchemilla'' (270), '' Sorbu ...

Chenopodiaceae Amaranthaceae is a family of flowering plants commonly known as the amaranth family, in reference to its type genus '' Amaranthus''. It includes the former goosefoot family Chenopodiaceae and contains about 165 genera and 2,040 species, making it ...

, Cruciferae,

Solanaceae The Solanaceae , or nightshades, are a family of flowering plants that ranges from annual and perennial herbs to vines, lianas, epiphytes, shrubs, and trees, and includes a number of agricultural crops, medicinal plants, spices, weeds, and o ...

Compositae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae we ...

and others.

Parthenogenesis Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and developmen ...

on these hosts allows large populations of aphids to build up quickly. The life span of a parthenogenic female is about twenty days in which time it can produce up to 85 nymphs. These mature in about twenty days at 10 °C and in about four days at 30 °C. As autumn approaches, the winged forms migrate back to the primary hosts. Here, both males and sexual females are produced, mating takes place and the females lay eggs which overwinter, ready to repeat the life cycle the following year. Predators include

midges A midge is any small fly, including species in several families of non-mosquito Nematoceran Diptera. Midges are found (seasonally or otherwise) on practically every land area outside permanently arid deserts and the frigid zones. Some midge ...

, lacewings,

syrphid fly Hover flies, also called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, while ...

larvae, anthocorid bugs and ladybirds (ladybeetles). Several members of the

Aphidiinae The Aphidiinae are a subfamily of tiny parasitoid wasps that use aphids as their hosts. Several species have been used in biological control programs of various aphids. Biology and distribution Aphidiines are koinobiont endoparasitoids of ad ...

and Aphelinidae wasp families are

parasitoids In evolutionary ecology, a parasitoid is an organism that lives in close association with its host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionary strategies within parasitis ...

of aphids. One which shows promise as a biocontrol agent is ''

Aphelinus asychis ''Aphelinus asychis'' is a parasitoid wasp native to Eurasia that was introduced to North America to control the Russian wheat aphid The Russian wheat aphid (''Diuraphis noxia'') is an aphid that can cause significant losses in cereal crops. ...

''.

Host plants

The cotton aphid has a very wide host range with at least 60 host plants being known in Florida and perhaps 700 worldwide. Among cucurbit vegetables, it can seriously affect

watermelons Watermelon (''Citrullus lanatus'') is a flowering plant species of the Cucurbitaceae family and the name of its edible fruit. A scrambling and trailing vine-like plant, it is a highly cultivated fruit worldwide, with more than 1,000 varie ...

cucumbers Cucumber (''Cucumis sativus'') is a widely-cultivated creeping vine plant in the Cucurbitaceae family that bears usually cylindrical fruits, which are used as culinary vegetables.cantaloupes, squash and

pumpkin A pumpkin is a vernacular term for mature winter squash of species and varieties in the genus '' Cucurbita'' that has culinary and cultural significance but no agreed upon botanical or scientific meaning. The term ''pumpkin'' is sometimes u ...

. Other vegetable crops attacked include

pepper Pepper or peppers may refer to: Food and spice * Piperaceae or the pepper family, a large family of flowering plant ** Black pepper * ''Capsicum'' or pepper, a genus of flowering plants in the nightshade family Solanaceae ** Bell pepper ** Chili ...

eggplant Eggplant ( US, Canada), aubergine ( UK, Ireland) or brinjal (Indian subcontinent, Singapore, Malaysia, South Africa) is a plant species in the nightshade family Solanaceae. ''Solanum melongena'' is grown worldwide for its edible fruit. Mo ...

okra Okra or Okro (, ), ''Abelmoschus esculentus'', known in many English-speaking countries as ladies' fingers or ochro, is a flowering plant in the mallow family. It has edible green seed pods. The geographical origin of okra is disputed, with sup ...

and

asparagus Asparagus, or garden asparagus, folk name sparrow grass, scientific name ''Asparagus officinalis'', is a perennial flowering plant species in the genus '' Asparagus''. Its young shoots are used as a spring vegetable. It was once classified ...

. It also affects

citrus ''Citrus'' is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus ''Citrus'' is nati ...

cotton Cotton 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 cellulose, and can contain minor p ...

and

hibiscus ''Hibiscus'' is a genus of flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. They include all forbs (flowering plants without a woody stem), gras ...

Economic significance

The adults and nymphs of the cotton aphid feed on the underside of leaves or on the growing tips of shoots, sucking juices from the plant. The foliage may become chlorotic and die prematurely. There is often a great deal of leaf curling and distortion which hinders efficient photosynthesis. Honeydew is excreted by the aphids and this allows sooty moulds to grow, resulting in a decrease in the quantity and quality of the produce. The aphids are a vector of crinkle,

mosaic A mosaic is a pattern or image made of small regular or irregular pieces of colored stone, glass or ceramic, held in place by plaster/mortar, and covering a surface. Mosaics are often used as floor and wall decoration, and were particularly pop ...

, rosette,

CTV CTV may refer to: Television * Connected TV, or Smart TV, a TV set with integrated internet North America and South America * CTV Television Network, a Canadian television network owned by Bell Media ** CTV 2, a secondary Canadian televisio ...

and other virus diseases. The aphids' impact is especially important on vegetable crops such as courgette, melon, cucumber, aubergine and strawberry and on cotton, citrus and mallow.

Insecticides

Carbamates In organic chemistry, a carbamate is a category of organic compounds with the general formula and structure , which are formally derived from carbamic acid (). The term includes organic compounds (e.g., the ester ethyl carbamate), formally ...

and

organophosphates In organic chemistry, organophosphates (also known as phosphate esters, or OPEs) are a class of organophosphorus compounds with the general structure , a central phosphate molecule with alkyl or aromatic substituents. They can be considered a ...

are commonly used against ''A. gossypii'' around the world.

Insecticide resistance

Resistance to carbamates and organophosphates has been traced to two variant

acetylcholinesterase Acetylcholinesterase (HGNC symbol ACHE; EC 3.1.1.7; systematic name acetylcholine acetylhydrolase), also known as AChE, AChase or acetylhydrolase, is the primary cholinesterase in the body. It is an enzyme that catalyzes the breakdown of acety ...

genes in ''A. gossypii'', MACE and MACE.

References

{{Taxonbar, from=Q2557995 gossypii Agricultural pest insects Insects described in 1877 Hemiptera of Africa Insect pests of millets