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Chromaphis juglandicola

Small walnut aphid

Description

Chromaphis juglandicola, known as the small walnut aphid, is a sap-sucking insect found on the underside of walnut (Juglans spp.) leaves. It forms dense colonies and secretes large amounts of honeydew, which supports the development of sooty mould. These visual effects reduce the ornamental value of trees, particularly in urban and park plantings. The species is widely distributed across Europe and often appears in warm, dry seasons. While the intensity of infestation is usually low, heavy aphid populations can reduce photosynthetic capacity and lead to a decline in overall tree vitality.

Symptom

Yellow aphids are present on the underside of leaves; sticky surfaces may be covered by dark sooty mould patches.

Tree Species: Walnut

Part of a plant- attacked: Leaf / Needle

Pest significance: Less harmful

Pest Category: Insects

Invasive Species: No

Present in EU: Yes