How to get rid of garden pests and bugs

British summers are usually a mix of thundery showers and clammy heatwaves – perfect conditions for many persistent garden pests, insects and bugs.

Garden pests such as aphids will thrive in these damp and warm conditions, breeding rapidly, invading stems of plants and sucking the life out of them; sawfly larvae can devastate roses; slugs and snails will feast on hostas, bedding plants and much more during rainstorms, and earwigs will munch on the leaves and flowers of your prized clematis, dahlias, carnations, chrysanthemums and delphiniums.

So as you get ready to sow, plant and re-arrange your vegetable beds and flower borders, now is the time to take steps to outsmart garden pests that can so often ruin your crops and leave plants in tatters.

There are a number of ways you can do this – cover vulnerable plants, put nuisance insects off the scent of prized crops, or simply install some sacrificial flora and fauna which will attract garden pests to them and away from other varieties.

3 easy ways to ward off garden pests

1. Use smelly plants

Pests can often be confused through scent, or simply don’t like the smell of certain plants. You can repel whitefly from valuable crops by planting French marigolds, Tagetes, next to them. The whiff of garlic and alliums, which are ornamental onions, can also keep pests at bay generally. Mixing highly scented plants together makes it more difficult for pests to find their favourite target. The strong smell of catmint, Nepeta, can deter flea beetles, while hyssop and mint put off cabbage white butterflies. Plant hedging barriers of fragrant plants such as lavender, hyssop, rosemary or southernwood around your whole vegetable plot to mask the scent of your veg from garden pests.

2. Create barriers

Place a barrier of grit or eggshells around plants which are frequently targeted by slugs and snails, such as hostas and lupins. Cover vulnerable young vegetable plants with fine-mesh crop-protection netting, or even old net curtains, and protect new brassica plantings with collars of horticultural fleece to stop cabbage root fly in its tracks. Cover newly sown carrots with horticultural fleece to deter carrot fly.

3. Use sacrificial plants

It may be worth losing some plants, in order to keep others. If you want your beautiful hosta leaves to remain undamaged, try planting Chinese lettuce nearby, which slugs also love – so this will hopefully give them enough food to feast upon without reaching the hostas. But remember to go on a slug patrol too and remove any of the little critters you spot on the sacrificial plants, to stop them breeding.

Grow nasturtiums and garlic to deter aphids from attacking your vegetable crops. Cabbage white caterpillars also love nasturtiums, so you might want to plant a row of them as an alternative menu to cabbages and broccoli, which the caterpillars would also devour. Some predators prefer certain varieties of veg to others. Slugs, for instance, are partial to the autumn-sown onion variety ‘Buffalo’, so if you mix this in with other onion types, the rest may escape relatively intact. Other sacrificial plants may include broad beans to attract red spider mite, nicotiana to lure whitefly, and potatoes to provide a feast for mealy bugs. You will have to dispose of these plants once the pests have taken hold, but at least this method should leave other crops untouched.

How to tackle 5 common garden bugs and pests

Once summer is fully underway, your garden may be under attack from a host of garden pests. Here are some ways to zap five common garden insects and pests including slugs and snails.

Aphids

There are more than 500 different species of aphid in Britain, including greenfly, blackfly, woolly aphids and even pink aphids, and many have particular host plants such as roses or beans.

These pests suck sap from the plants, distorting young shoots, and also excrete honeydew, which is sticky and encourages black, sooty moulds to grow. They breed rapidly – in optimum conditions the female gives birth to live young, missing out the egg stage. If there are enough of them, they can kill flower buds and spread viruses.

So you need to be vigilant. If you just have a few, you can rub them off affected stems with your fingers or give them a good blast with the hose. If the infestation is too large, spray soapy water over them. But the best deterrent is to encourage beneficial insects into your garden which will eat them, including ladybird larvae, parasitic wasps, lacewings and hoverfly larvae.

Earwigs

These little critters leave small round holes or notches in leaves and flower petals and tend to be active at night, so you might want to do a night patrol with a torch to hunt them out.

Alternatively, make your own traps out of upturned flower pots filled with straw or paper, which you can hang on canes among the tops of plants, providing shelter for adult earwigs overnight.

Empty them in the morning before they’re on the move – and you may want to relocate them where you have an invasion of aphids, as earwigs eat aphids as well.

Be comforted by the fact that the damage is purely cosmetic – they won’t kill your plants, they’ll just make them a little less pretty.

Red spider mites

These critters seems to come into their own in summer, and you need to keep your eye out for them on plants which are placed against sunny walls or in greenhouses or conservatories. They’re microscopic but create a fine web on the underside of leaves, which become yellow and dry and may even curl up. They won’t kill the plant but they will stunt its growth.

Help contain them by spraying affected plants with water once or twice a day to increase humidity, paying particular attention to the undersides of leaves.

Sawflies

Sawfly larvae will still be active in summer, particularly on apple and plum trees. While the adults are pretty harmless, they lay their eggs in the tiny fruitlets when the trees are still in bloom. The larvae then hatch and feed in the young fruit, leaving dark excrement in their wake. They can also damage geranium, geum and aquilegia, defoliating the plant extensively.

Pick off affected fruitlets as soon as you see them and don’t leave fallen fruits on the ground, which will result in the larvae escaping, burrowing into the grass and completing their life cycle.

Slugs and snails

Arguably the biggest nuisance in the garden, slugs and snails make light work of bedding plants and perennials, salad leaves and root vegetables, especially during or after a summer shower.

So, what can we do? Well, metaldehyde slug pellets are now banned but there are many other ways to keep them at bay, including beer traps, copper tape around pot rims, placing egg shells or other sharp material around vulnerable plants, or by introducing nematodes – natural microscopic organisms, which you apply by diluting them in water then watering them into the soil to kill the slugs underground.

I personally find that doing a slug and snail patrol after a sharp shower and picking off all I see, lifting the foliage from potted plants to seek out slugs which have climbed over to feast, is the best solution.

With toxic slug pellets now banned, here are 10 alternative ways to get rid of slugs