How to deal with common garden pests

The garden is a peaceful haven full of blooms, foliage and wildlife, but few gardeners will have escaped the odd unwelcome visitor.

Common garden pests

Pic: Getty

Garden pests are common in the UK, and some can be notoriously tricky to get rid of once an infestation has occurred. Here are some of the most common pests, and what you can do to see them off.

Otherwise known as greenfly or blackfly, these sap-sucking pests are easy to spot, as they gather on shoot tips, flower buds and on the undersides of leaves. As they suck the sap and inject leaves with their saliva, they can weaken the plant, and quickly spread disease from plant to plant, as well as excreting a sticky 'honey dew' substance, which often results in sooty mould. Aphids can stunt plant growth, and cause leaves to curl and wilt.

A hefty blast with the hose is often enough to dislodge the pests, but a greenfly insecticide will ensure they don't return. If you prefer to do things organically, try spraying diluted washing up liquid onto the aphids, as they breathe through their skin and this effectively suffocates them. Encouraging birds into the garden may also help, as they will happily gobble down these annoying pests.

Slugs and snails
A fiendish problem for gardeners, slugs and snails are notoriously difficult to deal with. They will attack all kinds of plants, leaving holes in leaves and munching on roots, and can be particularly deadly where young seedlings are concerned.

If you're not lucky enough to have a resident hedgehog or plenty of frogs and toads to keep the population under control, slug pellets are your first port of call. However, the active ingredient, metaldehyde, is poisonous to pets and small children, not to mention harming welcome wildlife. For a more environmentally-friendly option, try beer traps, or create barriers of wood ash or coal soot to keep these slimy pests at bay.

Vine weevils
These nocturnal bugs feed on almost any leaf or root, but are commonly the culprit if you're having a problem with azaleas, rhododendrons and fuschias. If you haven't spotted these shiny, black, night-time pests, look for notched edges to the leaves. Where adult weevils are already active, chemical insecticides, pirimiphos-methyl, bifentrhin or chlorpyrifos, can be used, but the best way to eradicate these plant-killing pests is to hit them at the larvae stage. Nematodes in the soil will go after the larvae before they reach adulthood.

Vine weevils are also partial to making their homes in greenhouses, and as such, keeping the area free of debris will give them fewer places to hide. Since they walk rather than fly, it is possible to protect pots with sticky tape covered in a non-drying glue.

Scale insects
These limpet-like insects get their kicks by sucking the sap from a wide range of plants, from houseplants to fruit trees and ornamentals, and cushion scales specifically are drawn to evergreen plants and shrubs. Not only do they weaken plants, like aphids they excrete honeydew on the foliage, encouraging the growth of black, sooty moulds. A major infestation will almost certainly cause poor growth. Look for scales or brownish bumps on plant stems and under leaves.

Once a soft scale infestation is under way, they can be tricky to get rid of, but chemical treatments containing pyrethrum, natural fatty acids, and rape seed oil are effective. If you catch it in the early stages, the scales can be cleared with a brush and water and destroyed. However, prevention is better than cure with these pests, so check bought plants thoroughly, and keep a regular eye on your plants so that you can deal with a potential problem before it really takes hold.

Red spider mites
Usually a problem in greenhouses, given the right conditions, the glasshouse red spider mite can cause damage outdoors. They love hot, dry weather, and attack the foliage of a wide range of plants, including fruits and vegetables, orchids and fuschia. The visible signs include a fine mottling on the surface of the leaf, and where a heavy infestation has occurred, a fine silk webbing can be seen. Left untreated, the leaves lost their green colour, dry up and fall off.

A soap spray is one way to treat the mites, though you will need regular applications and the plant will need to be washed off with clean water too. Insecticides containing bifenthrin are also effective, while those that contain plant oils or fatty acids can also help. Organic pesticides that use stinging nettle or garlic have also been found to work.

What are your garden pest bugbears? Have you found a way to treat them effectively? Leave your comments below...