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Garden pests - and how to get rid of them

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Insects and grubs are part of your garden’s ecosystem and are often harmless or beneficial. They’re only garden pests if they start causing damage to your favourite plants. But even then, you don’t have to reach straight for the pesticides. Here are some tips to help you get things under control as organically as possible.

Identify the problem

If you notice insects on a plant, the first step is to identify the species and find out whether they are likely to cause damage. It’s good to familiarise yourself with the most common garden pests, as some damage plants in ways that aren’t immediately visible. For example, aphids drink plants’ sap and transmit viruses, weakening them gradually and stunting growth. Noticing them early gives you the best chance of returning your plants to good health.

Aphid spotting tip: Aphids are tiny and come in lots of different colours, so be aware of different species and look out for tell-tale signs. A lot of ants on a plant may mean an aphid infestation, as ants feed on the honeydew secretion they produce.

Know and protect your natural allies in garden pest control

Most garden pests have plenty of natural predators. Ants can be helpful if you have a problem with grubs or caterpillars, but they also protect aphids from their natural predators (because they provide ants with food). Ladybirds, on the other hand, love to eat aphids - so much so, that they will fight ants to get them! Lacewings, tachinid flies and parasitic wasps are other handy allies against aphids, caterpillars and grubs.

Using pesticides (even natural ones) can kill or repel natural predators which could otherwise keep garden pests under control. Protect beneficial species by using pesticides as sparingly as possible. You can also encourage the beneficial species mentioned above by planting parsley, dill and angelica.

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Simple first steps

Dealing with garden pests doesn’t have to be complicated - simple solutions can also work wonders. For small, soft insects like aphids, a powerful shower with a garden hose is sometimes all your plants need.

If that doesn’t work, try a weak soap solution:

  • Mix 1 teaspoon of mild, eco-friendly soap or washing up liquid with 2 litres of water.
  • Test a small amount on a leaf for 24 hours to ensure it doesn’t damage the plant.
  • If the plant seems fine, spray it on the plant’s leaves using a spray bottle.
  • Remember to keep even mild homemade pesticides away from children and pets.


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Spice it up

You may like garlic and chili, but they are strong deterrents for garden pests. For an effective natural pesticide:

  • Blend the cloves of a couple of garlic bulbs with a few chillies, two cups of water, a good dash of vegetable oil and a generous squirt of eco-friendly washing-up liquid.
  • Strain the mixture and use just the liquid, diluting in 1 litre of water.
  • Test on one leaf and leave for 24 hours to ensure it doesn’t damage the plant.
  • If there are signs of damage, dilute the solution slightly and test again.
  • Otherwise, use a spray bottle to apply to affected plants every few days until the infestation has gone, then for an additional 10 days to tackle any eggs.

Remember: Natural pesticides can still kill or deter beneficial and harmless species, so use them only where really needed.



Caterpillars and butterflies

Caterpillars can present a bit of a dilemma to gardeners. On the one hand, they have very healthy appetites and may eat your favourite crops. On the other, they turn into butterflies and moths which are vital pollinators and are wonderful to see in the garden. For this reason, you may want to consider just leaving them where they are if they aren’t eating anything important.

But if they have moved into your vegetable garden, here are two options:

  • Remove them by hand and relocate them away from your crops.
  • Spray the plants lightly with a solution of 1 teaspoon of household vinegar per litre of water. Don’t make it any stronger, or you could damage the plants. If you remove them first, you can do this after to protect your plants from future invasions.
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Safety tip: Be very careful when handling caterpillars, as many have protective venomous spines which can cause skin irritations or worse. Look up the species first and wear gloves at all times. If you suspect the presence of oak processionary moth caterpillars, alert your local authority. Don’t try removing them yourself, as the irritating hairs they release when disturbed can lead to serious respiratory problems.

The vast majority of creepy crawlies in your garden aren’t garden pests at all. Enjoy learning about the roles that each species plays in your garden’s ecosystem and try to find natural ways of protecting your plants without upsetting the balance. These solutions tend to be cheaper and safer, and by involving natural allies, there’s also less work for you!