Why Is My Apricot Tree Covered in Aphids?

Aphids are among the most common pests on apricot trees in spring, colonising young shoot tips and the undersides of new leaves. The two species most commonly encountered on apricots in the UK are the mealy plum aphid (Hyalopterus pruni), which produces pale blue-green or greyish colonies with a powdery appearance, and the black bean aphid (Aphis fabae), which forms dense black colonies on young growth. Both feed by extracting sap from the plant, causing leaf distortion and secreting honeydew that allows sooty mould to develop.

When aphids are a problem

Small colonies of aphids on apricot trees are rarely a serious threat to the tree's health or fruit production. The situation warrants intervention when: colonies are very large and covering most of the young shoot tips; leaf distortion is severe enough to prevent normal expansion of new leaves; or the tree is very young and the growth being consumed is essential for establishing the framework. An established, healthy tree tolerates moderate aphid pressure without lasting damage.

Physical removal

For accessible shoot tips and small to moderate colonies, physical removal is the most targeted approach. Wipe colonies off with a gloved hand or cloth, or direct a firm jet of water at infested shoots. This does not require any chemicals and does not harm beneficial insects. Remove the most heavily infested shoot tips by cutting them back — this takes the aphids with them and the shoot will grow back from the bud below.

Soap-based insecticides

Insecticidal soap sprays (potassium fatty acids) applied directly to aphid colonies kill on contact without persisting in the environment. They are approved for organic use and do not leave residues. Apply thoroughly to the underside of leaves and to shoot tips where aphids congregate. Two or three applications at five-day intervals are more effective than a single treatment.

Encouraging natural predators

Ladybird larvae, lacewing larvae and parasitic wasps all feed on aphids and will naturally colonise and control aphid populations given time. Avoid any broad-spectrum insecticide applications during the spring — these kill predators as well as aphids and often worsen aphid outbreaks in the medium term by removing the natural control agents.