| Description: |
- Apterous adult: 1,5 - 2,0 mm long; body oval and relatively rounded; green with black siphunculi and cauda; legs and antennae paler and tipped with brown.
- Winged adult: thorax black; abdomen green with 3 pairs of black lateral circular spots on the anterior abdominal segments and a semicircular spot in front and behind each siphunculus.
- Egg: greenish-yellow to green, rapidly turning to shiny black. |
| Biology: |
- Host plants: apple, more rarely pear, hawthorn (Crataegus oxyacantha), medlar (Mespilus), quince, rowan or mountain ash (Sorbus), rose (Rosa) and spiraea (Spiraea).
Unlike most harmful aphids, A.pomi is an autoecious species.
- Number of female nymphs produced by oviparous females: 60.
Nymph: fundatrix developing in 3 weeks.
Aphids feed by inserting their stylets into the phloem. They often form compact sheaths on shoots, thousands of individuals sometimes being present. They infest the underside of terminal leaves which roll and undergo moderate leaf curl. |
| Life cycle: |
- Winter eggs hatch after bud-burst and give rise to fundatrices which are apterous parthenogenetic viviparous females producing a generation of viviparous parthenogenetic females.
- 10 to 15 generations succeed one another from spring to autumn.
- Winged forms appear from April onwards, migrating to other trees on which they deposit their eggs; light winds enable them to move more easily, carrying them to a distance of up to several dozens of kilometers.
- Winged oviparous females and apterous males appear in October and November. After mating, each female lays eggs on the twigs, preferably at the top of current year's growths. These eggs are sometimes grouped in large numbers, unlike those of other aphid pests. |
| Damage: |
- Feeding punctures of fundatrices and their offspring hinder growth of the young twigs of host trees and sometimes distort them. Damage is more severe on nursery stock and seedlings.
- In summer, sooty moulds develop on the honeydew sometimes which is produced in large quantities. |
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Photos: 24 |
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