Aphis pomi

De Geer, 1773

apple aphid, green apple aphid

Aphis pomi, the green apple , is a small sap-sucking insect specialized on pomoideous plants in the Rosaceae , particularly apple (Malus domestica). It is autoecious, completing its entire on a single host . The species reproduces primarily through during the growing season, with sexual forms appearing only in autumn to produce . It is morphologically similar to Aphis spiraecola but can be reliably distinguished by the length of the ultimate rostral segment.

Life-story of insects 06fig Aphis pomi by wikipedia. Used under a Public domain license.

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Snodgrass Aphis pomi D cropped white background by R. E. Snodgrass. [2]. Used under a CC0 license.

Pronunciation

How to pronounce Aphis pomi: //ˈeɪfɪs ˈpoʊmaɪ//

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Identification

Reliable separation from the morphologically similar Aphis spiraecola (spirea aphid) requires examination of the ultimate () rostral segment, which is longer in A. pomi; this character has a 100% correct identification rate in European . Wingless A. pomi lack the waxy coating present in woolly apple aphid (Eriosoma lanigerum). In eastern North America and Israel, A. spiraecola is more common on apple and has a faster reproductive rate, especially at high temperatures. Molecular identification via COI barcoding confirms boundaries.

Images

Habitat

Young growth of apple trees and related pomoideous plants in the Rosaceae ; specifically colonizes growing shoot tips and new leaf growth. Found in apple orchards, pear orchards, and natural stands of hawthorn, mountain ash, and other rosaceous .

Distribution

Widespread in Europe with pan-European distribution of predominant mitochondrial haplotype; western Asia extending to India and Pakistan; North Africa; North America including Canada and the United States. Distribution map records from: Austria, Belgium, Britain, Bulgaria, Czechoslovakia, Denmark, Finland, France, Germany, Hungary, Ireland, Italy, Malta, Netherlands, Norway, Poland, Portugal, Romania, Sardinia, Spain, Sweden, Switzerland, Yugoslavia, Afghanistan, Cyprus, Iran, Iraq, Israel, Lebanon, Pakistan, Syria, Turkey, Libya, Madeira, Tunisia.

Seasonality

hatch in spring; colonies develop on growing shoot tips through spring and early summer. Winged forms appear in June. Large build up by late summer. Sexual forms ( females and males) produced in autumn when drops below 11.8 hours and temperatures fall below 12°C light/8°C dark; egg deposition occurs after these conditions are met. Ten to fifteen may occur per season.

Diet

Phloem sap of pomoideous plants including apple (Malus domestica), pear (Pyrus communis), hawthorn (Crataegus monogyna), medlar (Mespilus germanica), quince (Cydonia oblonga), mountain ash (Sorbus aucuparia), and spiraea (Spiraea).

Host Associations

Malus domestica - primary apple
Pyrus communis - pear
Crataegus monogyna - hawthorn
Mespilus germanica - medlar
Cydonia oblonga - quince
Sorbus aucuparia - mountain ash
Rosa - rose
Spiraea - spiraea

Life Cycle

Hemimetabolous development with no true pupal stage. hatch in spring into fundatrices (stem mothers). Successive of parthenogenetic females produce live young on growing shoot tips. In June, winged parthenogenetic females (alatae) are produced for to other branches and trees. Autumn conditions trigger production of sexual forms: winged females and wingless males. After mating, eggs are laid near shoot tips, initially green then turning black. Autoecious completes entire cycle on single species without host alternation.

Behavior

Forms dense colonies on growing shoot tips causing leaf edge curling. attendance is common; ants feed on honeydew and protect colonies from and . When disturbed, individuals drop from plants. Winged forms disperse by wind over many kilometers.

Ecological Role

Herbivore that can cause stunted shoot growth, fruit disfigurement, and premature leaf fall in young trees at high levels. Honeydew promotes growth. Serves as prey for including European earwig (Forficula auricularia), lady beetles, and such as Aphidius ervi. mutualism modifies predator-prey dynamics by deterring natural enemies.

Human Relevance

Economic pest of apple and pear production; damage includes curled leaves, stunted growth, and fruit quality reduction. Management complicated by morphological similarity to Aphis spiraecola, which has different susceptibility. Attract-and-kill strategies developed for other apple pests may have applicability. Subject of molecular identification research to improve field-based discrimination for targeted pest management.

Similar Taxa

Aphis spiraecolaMorphologically similar spirea aphid; distinguished by shorter ultimate rostral segment, faster at high temperatures, and broader range; more common in eastern North America and Israel
Eriosoma lanigerumWoolly apple aphid; distinguished by dense woolly wax coating and different body shape; also a pest of apple but has different including root-feeding forms

More Details

Genetic characteristics

Mitochondrial COI analysis reveals one predominant haplotype with pan-European distribution. Nuclear EF-1α sequences are identical across analyzed , indicating low genetic diversity compared to the more genetically complex Aphis spiraecola.

Population dynamics

Under controlled autumnal conditions, remains static until defoliation; forms disappear and levels off at of 13.3 hours and 17°C light/12°C dark. production equals approximately one-third of autumn size under favorable conditions.