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Aphids on apple (Malus)On this page: Species lists Aphis pomi Rhopalosiphum oxyacanthae (=insertum) Dysaphis plantaginea Ovatus crataegarius Eriosoma lanigerum Dysaphis devecta Species of apple
Aphids on apple
Blackman & Eastop list about 49 species of aphid which feed on apples, Malus domestica (Apple, European Crab-apple, Paradise Apple) worldwide, mostly in the genera Aphis, Dysaphis, Eriosoma, Ovatus and Rhopalosiphum.
Of those aphid species, Baker (2015) lists 21 as occurring in Britain: Aphis aurantii, Aphis craccivora, Aphis fabae, Aphis gossypii, Aphis pomi, Aphis spiraecola, Aulacorthum solani, Dysaphis anthrisci, Dysaphis brancoi rogersoni, Dysaphis chaerophylli, Dysaphis devecta, Dysaphis plantaginea, Dysaphis radicola group, Eriosoma lanigerum, Macrosiphum euphorbiae, Macrosiphum rosae, Myzus persicae, Nearctaphis bakeri, Ovatus crataegarius, Ovatus insitus, and Rhopalosiphum oxyacanthae.
About six species are commonly encountered on the orchard apple (Malus domestica) and crab apple (Malus sylvestris) in UK: Aphis pomi, Rhopalosiphum oxyacanthae, Dysaphis plantaginea, Ovatus crataegarius, Eriosoma lanigerum and Dysaphis devecta.
These 6 species are listed below in rough order of abundance. Assistance on distinguishing the two species of apple is given below.
Aphis pomi (Apple aphid)
The aptera (below first) is bright apple green or yellow green and is not wax-powdered. The abdominal dorsum is pale and membranous usually without dark bands or sclerites. The siphunculi and cauda are conspicuously blackish. The body length of apterae is 1.2-2.2 mm. The alates have some variably developed dorsal bands. Colonies are often attended by ants (below second).
The apple aphid does not host alternate. It feeds on Apple (Malus spp.) and related plants including pear (Pyrus), hawthorn (Crataegus), and Cotoneaster. It is distributed throughout Europe, north Africa, Asia eastwards to India and Pakistan, and North America.
Rhopalosiphum oxyacanthae (= insertum) (Apple-Grass Aphid)
The apterae on apple are small elongate-oval light green to yellow-green aphids They have fairly well-marked dark green stripes down the centre of the back and along each side. The frontal head tubercles are low, with the median tubercle about the same height as the antennal tubercles. The siphunculi are of moderate length - about one tenth as long as the body - and pale with dusky tips. The 5-segemented antennae are about a third the length of the body. The winged viviparae have blackish head, thorax and siphunculi and a green abdomen with some brown plates and pigmentation. The body length of apterae on apple is 2.1-2.6 mm.
The apple-grass aphid host alternates between Apple and related species in the Rosaceae: and the roots of various Grasses (Poaceae). It has a sexual stage in its life cycle with eggs laid on Apple. The apple - grass aphid is found in Europe and Japan.
Dysaphis plantaginea (Rosy apple aphid)
A medium-sized globe-shaped aphid which is purplish-olive-green to mauve and covered with a whitish wax pubescence (below first). The antennae of apterae are at least as long as distance from the frons to the base of the siphunculi. The aptera is without pigmentation on the abdominal tergites anterior to the siphunculi (these two characteristics enable one to differentiate Dysaphis plantaginea from members of the Dysaphis anthrisci / devecta group, which have shorter antennae and dorsal pigmentation spots anterior to the siphunculi). The siphunculi are quite long compared to other Dysaphis species, blackish brown and tapered with flanged tips. The cauda is dark, short and triangular. The body length of the aptera is 2.1-2.6 mm. Colonies are often attended by ants (below second).
The rosy apple aphid host lives in spring on apple (Malus spp.) where it forms yellowish crumpled leaf galls. (Spring generations of the Dysaphis anthrisci / devecta group roll and redden the lateral margins of leaves of apple.) Aphids remain on apple until mid-summer by which time attacked shoots are stunted and twisted. Fruits from infested shoots are small and malformed. Alates then migrate to the secondary host plantain (Plantago) where they form colonies along the veins. The species occurs in Europe, Africa, much of Asia and North and South America.
Ovatus crataegarius (Hawthorn - mint aphid)
The aptera of the hawthorn-mint aphid (below first|) is yellow-green to apple-green, sometimes mottled with darker green markings. The antennae are curved and about 1.2-1.5 times the length of the body. The pale siphunculi are 1.7-2.6 times as long as the tongue-shaped cauda. The body length of apterae ranges from 1.5-2.0 mm. The colony shown (below second) is on young hawthorn leaves.
The hawthorn - mint aphid host alternates from hawthorn and apple (Rosaceae) to mint (Mentha, Lamiaceae) where it can reach pest status. In warmer climates it may overwinter viviparously near the ground.
Eriosoma lanigerum (Woolly apple aphid)
Wingless females on the secondary host are purple, red or brown and are covered in thick white flocculent wax. This is produced by distinct wax glands on the head and along the thorax and abdomen. The six segmented antennae are 0.17-0.24 times the length of the body. The body length of apterae is 1.2-2.6 mm. Winged viviparous females (fourth instar alatiform nymphs shown in the picture below left) are reddish brown with very small wax glands and consequently much less wax. Their antennae are about 0.4 times the length of the body.
The wingless females live in dense colonies (see picture above right) on the roots, trunk or branches of the (secondary) host apple (Malus) and related species, often causing deformation and cancer-like swellings of bark. Sexual forms appear to have been lost, and overwintering is in fissures on the lower part of the trunk and on the roots. It is a pest of apple throughout the world.
Dysaphis devecta species group (Rosy leaf-curling apple aphids)
The Dysaphis devecta species group includes three species: Dysaphis devecta, Dysaphis anthrisci and Dysaphis chaerophylli. All members of the Dysaphis devecta group roll the edges of apple leaves and turn them red to produce a characteristic gall on apple (see first picture below). Late spring colonies of Dysaphis devecta sensu stricto (which do not host alternate) include many apterae or alatiform apterae with sclerotized thorax. Apterae are bluish-grey and wax-powdered; alatiform apterae are dark green to reddish. Late spring colonies of other members of the group (Dysaphis anthrisci & Dysaphis chaerophylli, both of which host alternate) include many immatures and adult alates. The pictures of the alate (see second picture below) and immatures below appear to be of one of the latter two species.
Dysaphis devecta remains all year on apple and has no alternate host. Sexual morphs appear before mid-summer, after only three parthenogenetic generations, and overwintering eggs are laid on apple. Dysaphis anthrisci host alternates between apple and cow parsley (Anthriscus sylvestris). Dysaphis chaerophylli host alternates between apple and the leaf bases of various Chaerophyllum species. Members of the Dysaphis devecta species group are found in Europe.
Species of apple
Worldwide, the Malus genus comprises perhaps 30-55 species.
The two most common apple species in Britain have pedicels that are shorter than the mature fruit.
Stace (2010) lists five other introduced species. These have pedicels at least as long as their mature fruit.
Two species are considered naturalized in UK.
The remainder are described as "street trees", and seldom self-seed.
There are undoubtedly other apple species, hybrids and cultivars in UK gardens, parks and streets. Below are mature fruit of an unidentified specimen, possibly a hybrid of Malus floribunda or Malus baccata.