Aphids: how to spot, prevent and treat them pest
How do you spot aphids?
Colonies of small aphids sit on the shoot tips and the underside of the leaves. The leaf curls and puckers, and sticky honeydew is left on everything below. The viruses they carry are more dangerous than the feeding itself.
How do you prevent aphids?
Go easy on nitrogen, because soft sappy growth is what aphids are looking for. Encourage the predators (ladybirds, lacewings, parasitic wasps). Use a reflective mulch, which puts them off settling, and a strong jet of water to knock the colony off the tips.
On a particular plant
tulip: Check the stored bulbs as well, because aphids settle on them in store and not only on the leaves.
What works against aphids?
Potassium soap works on contact and only while it is wet, so it has to reach the underside of the leaf. On drought-loving plants and in heat it can scorch, so apply it in the evening.
Check the registration and the label before use.
Which plants get aphids? 56
Vegetables 8
Herbs 5
Fruit trees 15
Berries 6
Ornamentals 22
Sources: Clemson Cooperative Extension, Royal Horticultural Society, University of Wisconsin-Madison Division of Extension, Utah State University Extension
Checked on 28 August 2026.