When you’re growing, well, just about anything, there’s one pest that rears its head time and again: the ever-present aphid! These tiny, soft-bodied insects will attack many plants, leaving them weakened and prone to disease. As a gardener you have the power to fight back, so read on or watch our video to discover five ways for controlling aphids without resorting to pesticides.
What are Aphids?
Aphids are small, soft-bodied insects. All types are less than a tenth of an inch (3mm) long but there are many different species, from the black bean aphid to the rose aphid or greenfly. They come in a range of colours, from white or grey, to green through to black.
Aphids can be quite secretive. Look for them on new growth, in leaf crevices, clustered on buds, along stems or under leaves. The tiny insects are usually found in groups and you may find some with wings - a sign that the colony is about to disperse onto new host plants. Woolly aphids are easier to spot; they shield themselves in a mass of white, woolly wax on tree branches.
Aphids suck plant juices, which weakens the host plant, causing slow and stunted growth. Leaves may become mottled, yellowed or curled, and prolonged feeding may eventually kill the plant. Some aphids also transmit harmful plant diseases.
Controlling Aphids Organically
Most gardens will see the first aphids appear by early summer. Thankfully it’s easy to stop aphids from ruining your crops. Here are some ideas to banish these bothersome bugs.
1. Squash and Remove
Start by checking plants regularly for any signs of aphids. As soon as you spot any, squash them by hand. Clusters of locally concentrated aphids, for example at the tips of shoots, may be nipped off in their entirety and destroyed. Pinch out the tips of broad beans once the first pods appear to make the plants less attractive to black bean aphids.
2. Blast Them Off
Try blasting small infestations of aphids off your plants with a jet of water from a hosepipe. Adjust the nozzle or cover the end of the pipe with your finger to force the water out at higher pressure. The aphids will be knocked off and fall to the ground, and will be unlikely to return to the plant.
3. Spray Soapy Water
Or, spray infected plants with soapy water. Add a couple of drops of dish soap to a spray bottle, top up with water and shake to dissolve. Spray the solution liberally over the plant, remembering to reach all parts of the plant, including the undersides of leaves. The soapy water traps and suffocates the aphids.
4. Cover Vulnerable Vegetables
Winged aphids can quickly spread plant diseases such as cucumber mosaic virus. To avoid this, cover susceptible plants with row covers in midsummer, when the risk of this disease is highest. Vulnerable plants include cucumber, spinach and celery, so prioritise covers for these vegetables.
5. Attract Aphid Predators
Where you find aphids, you’ll also find aphid predators. Ladybirds (especially their larvae) have a voracious appetite for these soft-bodied insects. Hoverfly larvae also munch their way through aphids, as do lacewings and many types of tiny parasitic wasp.
You can attract these beneficial insects to your garden by planting a range of flowering plants. Plants with simple, single flowers are best, for instance poached egg plant, marigolds, calendula, alyssum, buckwheat and echinacea. Flowering herbs such as dill, fennel, parsley, thyme and mint are also a magnet for predators. Grow these plants next to your vegetables so that beneficial bugs come to feed – and bring their appetite for aphids with them!
Aphids are part and parcel of growing your own food, but they needn’t gain the upper hand. Of course, if you have other methods you use to banish aphids, do share them by posting a comment below.
We’d also love you to take part in The Big Bug Hunt, an international research project we’re running to track the spread of all bugs, including aphids. Pop by the website and report any bugs you find in your garden. By tracking where and when bugs appear, we aim to develop a pest early warning system for gardeners – something I know I could certainly do with!