Common Garden Pests & How to Manage Them
Every garden has pests. The goal is not to eliminate them entirely — that would be neither possible nor desirable — but to keep populations at a level where they cause minimal damage. A healthy, biodiverse garden is the best long-term defence.
Slugs and Snails
The most common and damaging garden pests in the UK. They feed at night and in wet weather, targeting seedlings, hostas, lettuces and many other plants. Control methods include: hand-picking after dark, copper tape barriers around pots, encouraging natural predators (hedgehogs, frogs, ground beetles), nematode biological controls (effective in warm, moist soil), and iron phosphate pellets (safer for wildlife than metaldehyde). Avoid leaving debris and damp hiding places near vulnerable plants.
Aphids
Greenfly, blackfly and other aphids cluster on soft new growth, sucking sap and excreting sticky honeydew that encourages sooty mould. A strong jet of water will dislodge them. Encourage natural predators — ladybirds, lacewings and hoverflies. Avoid over-feeding with nitrogen, which produces the soft growth aphids prefer. Insecticidal soap or neem oil are effective organic treatments for severe infestations.
Vine Weevil
The adult vine weevil notches the edges of leaves, but it is the white, C-shaped larvae that cause serious damage by eating plant roots. Container plants are particularly vulnerable. Check the roots of any plant that wilts unexpectedly. Biological control using nematodes (Steinernema kraussei) is effective when applied to moist compost in late summer or early autumn. Repot container plants in fresh compost each year and inspect roots carefully.
Caterpillars
Cabbage white butterfly caterpillars can devastate brassicas. Cover plants with fine mesh netting from June onwards to prevent egg-laying. Check the undersides of leaves regularly and remove egg clusters and young caterpillars by hand. Bacillus thuringiensis (Bt) is an organic biological control that is effective against caterpillars.
Lily Beetle
The bright red lily beetle and its larvae can strip lilies and fritillaries bare. Check plants regularly from April onwards and remove adults, larvae and eggs by hand. They drop to the ground when disturbed, so hold a container beneath the plant. There are no effective biological controls currently available in the UK.