How to get rid of aphids

Aphids damage plants by sucking their sap. Read our guide on how to get rid of all types of aphid including woolly aphid and root aphid
Ceri ThomasEditor, Which? Gardening

Take a look at our other guides on how to get rid of aphids: 

How to get rid of woolly aphids

This aphid (Eriosoma lanigerum) arrived in Britain in the 18th century and is now very common. Woolly aphids feed on apples and ornamentals that are closely related, such as crab apples, chaenomeles, cotoneaster and pyracantha.

How do I recognise woolly aphid?

You will not see the small, brown or greyish-purple aphids, but rather their woolly protective coating which is white and waxy. This coating looks rather like a fungus, especially when the woolly aphids cluster together in large numbers.

Woolly aphids feed on sap and are attracted to younger, woody shoots and damaged areas such as pruning wounds. Unsightly galls form where aphid colonies have attacked. These can split, letting in diseases such as apple canker.

Woolly aphids don’t attack the roots, but they can infest the base of the trunk.


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When should I expect to see woolly aphid?

They overwinter as young aphids. These are not covered by waxy strands, so they are hard to spot. In March and April they become active, and soon breeding colonies covered in a white, woolly coating will be noticeable.

They spread by producing crawling young which find new areas to colonise then produce young. In July winged forms fly off to infest other plants. Breeding stops in autumn when immature aphids seek sites to overwinter.

How much of a problem are woolly aphids?

On a healthy tree, woolly aphid is unlikely to do much damage, though it can harm young trees or those weakened by disease or poor growing conditions However, sticky masses can be a nuisance when harvesting fruit.

Infestations are often kept in check by predators. Both native predators, such as ladybirds, hoverflies and lacewings, and an introduced parasite attack woolly aphids.

The introduced parasite, a tiny wasp (Aphelinus mali), now lives wild in southern England and is especially effective during hot, dry years. You can tell that this parasitic wasp is at work in your garden if the wool has been reduced, leaving a shiny, blue-black, naked aphid with a circular hole in its back through which the parasite has made its exit.

Although this parasite is very susceptible to insecticides, it will thrive in an organic garden.

Learn how to grow fruit

How can I control woolly aphid?

Watch for signs of woolly aphid in the spring. Scrub them off using a toothbrush dipped in water with a drop of detergent in it. 

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How to get rid of root aphids

Root aphids are greenfly-like creatures which live on the roots of plants. Just like their counterparts above ground, they feed by sucking sap, but from roots instead of stems or leaves. They are not easily seen, but they are a common pest.

How do I know if root aphids are present?

When plants wilt, are stunted, have unhealthily coloured foliage and lose leaves prematurely, suspect root aphids. Remember that other factors, especially drought, can have the same effect. Often there will be many ants around infested plants, feeding on the honeydew aphids produce, even below ground.

What do root aphids look like?

They usually look like a waxy mould or powder on the roots of the affected plants. They can build up to huge numbers. The affected roots often split.

What could I mistake root aphids for?

Mealy bugs also infest roots of pot plants indoors and could be mistaken for root aphids.

Some harmless fungi cover roots with a powdery covering. Look out for the tiny aphids.

Apples can sometimes have woolly aphids on their roots, but this is not a true root aphid, being mostly a pest of shoots and trunk.

Ants are thought to take a few ordinary aphids into their nests, which may be around the roots of plants.

Can do you control root aphids?

The damage they cause is worst in dry conditions, so keeping plants watered will often help them shake off an attack. In the case of lettuce, plants may survive long enough to heart up and be harvested.

If you catch infestations on pot plants early enough, plants can be saved by washing off the aphids from affected roots and repotting in fresh compost.

Covering lettuce with insect-proof mesh – from June until August prevents the aphids getting to their roots.

There is no chemical control for root aphids, so try to avoid the problem or grow a resistant variety.

Discover the best protective covers

Can root aphids be avoided?

Only lettuces sown or planted between mid-April and the end of June are at risk. At these times use resistant varieties. Other root aphids probably can't be avoided.

Which varieties are resistant to root aphids?

The following varieties of lettuce are resistant: 'Debby' and 'Lakeland' (butterhead); 'Salad Bowl' (oak leaf); and 'Beatrice' (iceberg). 'Little Gem' (cos) is also tolerant of root aphid.

Learn how to grow lettuce

What should I do with affected roots?

Composting, burning or burying affected plant material will reduce the number of survivors. Always aim to get rid of as much of the aphid-infested root and surrounding soil and compost as possible. Avoid growing susceptible plants in the same soil or site for a year.

How to get rid of black-bean aphids

What is black bean aphid?

Also known as blackfly, this is the most serious pest of broad beans but also attacks French and runner beans later in the summer and ornamentals, including dahlias, poppies and nasturtiums. It overwinters on shrubs such as euonymus, Viburnum opulus and philadelphus.

Read our guide to how to grow broad beans

Does black bean aphid cause serious damage?

A single winged female landing on a broad bean plant from May onwards can create a large colony very quickly, thanks to their prodigious reproductive rate. Live young can in turn give birth within a week as temperatures rise.

Ants farm and protect the colonies and can spread the infestation further. Each aphid punctures the stems of the plant and feeds on the sap. Severe attacks can seriously weaken the plant and the sticky honeydew excreted as a waste product encourages surface moulds.

How do I control black bean aphid?

One approach is to inspect the crop twice weekly from May onwards, paying particular attention to the growing tips. Individual blackfly can be squashed and small colonies can be removed by pinching out the growing tip. Take care to remove every aphid, since survivors will continue to multiply. Once four or five flower trusses have formed pinching out all tips will remove the most tempting part of the plant for aphids and concentrate the plants' efforts on producing pods.

Alternatively you can spray with a suitable insecticide.

Try the five easiest veg to grow