Aphids

Aphids (greenflies)

1. Identification

• Common name: Aphids, greenflies
• Scientific name: Various species (e.g.: Aphis spiraecola Patch, Aphis pomi De Geer, Aphis gossypii Glover, Myzus persicae Sulzer, Brachycaudus amygdalinus Schouteden, Dysaphis plantaginea Passerini)
• Order: Hemiptera
• Family: Aphididae

2. Pest description

• Small sucking insects, with a soft, pear-shaped body.
• Variable colouration: green, yellow, black, brown or pinkish.
• Presence of siphunculi on the abdomen, characteristic of the group.
• They form dense colonies on young leaves, shoots and buds.
• They may present apterous and alate forms, the latter responsible for dispersal.

3. Main hosts

• Stone fruits (peach, plum, apricot and others).
• Pome fruits (apple, pear, quince and others).
• Citrus (orange, tangerine, lemon and others).
• Vegetables (solanaceous, cucurbitaceous, brassicaceous and others).
• Ornamentals and spontaneous plants.
• Many species are polyphagous; others alternate between trees and herbaceous plants (heteroecious cycle).

4. Symptoms and damage

• Curling, deformation and yellowing of young leaves.
• Reduced vegetative vigour and stunted growth.
• Excretion of honeydew, favouring sooty mould.
• Decline in the commercial quality of the fruits due to soiling and sooty mould.
• Transmission of viruses in various crops.

5. Biological cycle

• Several annual generations, with predominantly parthenogenetic reproduction.
• In cold regions, some species overwinter as eggs.
• In warm regions, they may remain active all year round.
• Populations increase rapidly in mild weather and in young, vigorous tissues.
• Alate forms allow dispersal and colonisation of new plants.

6. Monitoring

• Direct observation of young leaves, shoots and buds.
• Assessment of the presence of colonies, honeydew and sooty mould.
• Counting of individuals or colonies per shoot to support decision-making.
• Regular monitoring during periods of active plant growth.

7. Management measures

• Cultural: Removal of heavily infested shoots; clean-up pruning; avoiding excess vegetative vigour; balanced management of nitrogen fertilisation.
• Biological: Conservation of beneficials such as Coccinellidae, Syrphidae, Chrysopidae and Aphidiinae parasitoids.
• Integrated protection: Intervention only when population levels justify it; preference for selective methods compatible with beneficials; avoiding unnecessary treatments.

Bibliographic references

• Blackman, R. L., & Eastop, V. F. (2000). Aphids on the World’s Crops. Wiley.
• Blackman, R. L., & Eastop, V. F. (2006). Aphids on the World’s Herbaceous Plants and Shrubs. Wiley.
• van Emden, H. F., & Harrington, R. (2017). Aphids as Crop Pests (2nd ed.). CABI.
• Dixon, A. F. G. (1998). Aphid Ecology: An Optimization Approach. Chapman & Hall.
• EPPO Global Database – Aphididae.
• CABI Invasive Species Compendium – Aphididae.
• Hales, D. F. et al. (1997). Aphids: Their Biology, Natural Enemies and Control. Elsevier.
• Hullé, M. et al. (2020). Aphids in Agriculture and Horticulture. INRAE.