Dealing with pests

Trying to control pests organically is not an easy task, you have to try and work together with nature, it’s about trial, error and good husbandry. There are a number of options out there but it’s all about discovering what works best for you and your garden.

The healthier the plants the more able they will be in fighting off attack. Try to give them the right soil conditions, plant them in the right place, sow the seeds at the right time of the year. Try not to overcrowd your plants or let them get over run with weeds as all these things can attract unwanted attention.

Look after them well when they are young, avoid stressing them out and you will give them the best possible chance. Remove affected material at the first sign of attack. Bag it or burn it but never put it on your compost heap as spores will stay in the soil waiting for the chance to strike again.


Most pests have their own predators, so by attracting these into your plot or garden they will start controlling the unwanted bugs for you.

Good Predators - the ones to encourage

Centipedes will eat slugs and snails

Beetles eat slugs, larvae and root aphids

Hoverflies, ladybirds and lacewings love to snack on aphids, mealy bugs, mites and small caterpillars.

Earwigs will eat caterpillars, aphids and codling moth eggs.

Birds eat a wide range of pests including caterpillars, larvae and other soil-borne grubs

Frogs, Toads,Newts and Slow worms love to eat slugs


One of the best ways to attract most of the above predators would be to build a pond. It doesn't have to be huge, just a small amount of water is enough to attract an abundance of wildlife. As well as providing a perfect habitat the pond also provides a source of drinking water for many other creatures. Any water tight container can be used to make a pond, this pond on the left was made using an old bath and the wildlife moved in about an hour after it was finished. Always try and cover open water with some form of safety netting or wire mesh especially if children are around.

Surround your pond with a number of different habitats to attract a wide range of creatures. Provide lots of hidey holes in the form of an old log pile or stones as well as a small overgrown area for animals and insects to over winter. You can make insect hotels for the likes of bumble bees, ladybirds or lace wings, just tie together a bundle of garden canes cut down to about 15cm long this will provide good shelter for them. A great place to look for other ideas for helping insects is the Wiggly Wigglers website.

Another way of attracting wildlife could be to set aside a disused allotment plot or patch of garden and turn it into a small nature reserve.  Find information on the best plants and trees for attracting insects here.

Some of the most common pests and how to deal with them.

Ants -These tiny insects can be a big nuisance in the garden. They swarm over plants and trees that are infested with aphids in search of the honeydew excreted by them and transport them to new crops.
Ants build nests in your soil and by tunnelling underground damage the roots of plants and often kill them. They feed on newly sown seed and can be seen swarming over ripening fruit.

DEAL WITH THEM - To control ants destroy nests with a liquid derris or a kettle of boiling water. a good dusting of ant powder also works well.

Aphids (Greenfly and Blackfly) - Aphids are one of the most common and most troublesome of all our allotment pests, attacking a large number of plants. They suck the sap of the plant and prefer the tasty new shoots. It is unlikely the plant will die but it can be seriously weakened, resulting in a lower yield.

It helps if you understand a few basic facts about the life of an aphid this will give you a better chance at managing them. Aphids reproduce very quickly when the conditions are right. During the spring and summer months the female aphids give birth to live offspring (they don't lay eggs) these are all female. Towards the end of the summer male aphids are produced, and mated females lay eggs that hatch the next spring. When a plant becomes overrun with aphids, winged individuals are produced which then search for a less crowded plant. Many aphids excrete honeydew, a sugary liquid which ants love to collect. They attack the tissue of stems, leaves and fruit to suck out the sap.

FACT - Colonies of aphids build up more rapidly under glass

The spores of sooty mildew fungus germinate in the poo of aphids, producing a thick sooty covering on the leaves of plums, pears, apples and asters. This mould does not harm plants but is unsightly and may spread to the fruit.

SPOT THE SIGNS! - Direct damage includes leaf-curl and distortion of young shoots, A thick sooty covering on leaves.

Aphids are a virus carriers and indirectly damage plants by sucking infected sap from a diseased plant and carrying it to a healthy one. Aphid can multiply at an alarming rate, so as soon as you spot them pick off infested shoots.

DEAL WITH THEM - Pick off infested shoots, or wash off with a spray hose, or you could try derris powder for bad infestations. A mild solution of washing up liquid in water can be used as a spray with some success. The best way as always is to encourage your friendly predators as most love to eat aphids.

Try not to over fertilize as too much fertilizer creates sappy new growth which the aphids love, organic fertilizers work best as they release the nutrients slowly. Plants that have been given the best start and have not been stressed are more likely to fend off aphid attacks.

TOP TIP - Have you spotted any ants? Some ants care for aphids so they can feed on their honeydew but at the same time the protect the aphids from natural enemies. In order to successfully manage your aphid problem, you'll need to deal with these ants. A sticky band of material (available from garden centres) around the trunk of your infested tree will stop the ants getting to the aphids.

Big bud mite - These mites live in the leaf buds of blackcurrants which swell to an abnormal size and eventually wither and fall off.
This Mite also affects red and white currents, but the buds do not swell before they fall off. It is important to control these mites as they are responsible for the spread of a virus disease called reversion, which causes the rapid falling off of fruit when cropping. If bushes are badly attacked they must be destroyed.

DEAL WITH THEM - There are no pesticides available for the control of big bud mite. Get rid of heavily infested plants after the fruit has been picked and replant in the autumn. There is a mite resistant cultivar called ‘Ben Hope' available. You can pick off affected buds of lightly infested plants in winter

Cabbage root fly- The larvae attack brassica roots, causing wilting and collapse of plants.

The white larvae of these fly’s tunnel into many root vegetables such as swedes, turnips and radishes. They also attack the roots of newly planted cabbage or other brassica seedlings.

SPOT THE SIGNS! - The plants turn a bluish colour, wilt and die this can happen overnight.

DEAL WITH THEM - Remove any infected plants immediately and destroy. You can apply a nematode based insecticide immediately after planting out or try putting discs made of roofing felt around the base of stems. alternatively place a fine netting over young plants as soon as they go in.

Carrot Fly- The larva of this pest tunnels its way into the carrot roots causing them to rot.

Carrot fly larvae and pupa. 
Carrot fly can wipe out rows of carrots in no time and can also effect parsnips, seedlings are killed and mature roots are often found riddled with maggots.

FACT - Attacks are often worse on dry soils.
SPOT THE SIGNS! - Look for reddish leaves and wilting foliage at a later stage the leaves turn yellow, maggots around the base of mature carrots.

DEAL WITH THEM - Unfortunately there is no treatment, try preventing this pest by sowing seeds thinly and destroying all thinning's. Try covering seedlings with horticultural fleece in spring. Pick crops in the evening when these pests are less active adults are attracted by the carrots scent. Carrots also benefit from companion planting.

Caterpillars - Considered a menace by most gardeners they mainly feed on the foliage of plants.

Cabbage white caterpillar - Your whole crop will be wiped out if you don't keep on top of this pest. Caterpillars hatch out from eggs in Spring and begin feeding immediately. They pupate in summer and hatch out of their chrysalis in Spring to mate.

SPOT THE SIGNS When holes start appearing in leaves. inspect the underside of leaves regularly especially if you see white butterflies hovering over your cabbages. Eggs are small yellow cone shapes often laid in clusters, crush and remove any that have been laid.

DEAL WITH THEM The best way to prevent attack, is to cover up your Brassica's straight after planting with a fine netting, as they squeeze through the smallest gaps. Check it regularly for any holes or gaps.

Flea beetle - The are many different types of these small beetles and they can ruin vegetable crops. They can destroy a whole bed of seedlings by chewing off your young plants at ground level.

Flea Beetle damage.
Plants that tend to suffer most include members of the brassica family i.e. cabbages and broccoli, rocket, Mitzuna pak choi, peas and even turnips and radishes.

SPOT THE SIGNS! - Leaves of plants are covered with many tiny holes.

DEAL WITH THEM - Flea beetle can be worse in dry weather so keep plants damp with a regular spaying of water which the flea beetle doesn't seem to like. For a really organic alternative try soaking garlic in water for a few days and spraying on your plants with the strained mixture, really smelly but it has been known to work.

Leek Moth - Pale green caterpillars feed inside young stems and leaves until only the outer skin remains.

The moth pupates inside a silk-like net.

Destroy badly affected leaves. Also effects onions and shallots.  Leek moth can be devastating, reducing your once beautiful leeks to a smelly mushy pulp. There is no effective insecticide available for use on leeks and onions.
DEAL WITH THEM Ways to prevent this include growing plants under fleece which prevents moths laying their eggs. Keeping your leeks well-watered will help ensure strong growth as larger plants are a lot more able to survive and produce an edible crop.  Also good crop rotation will help to reduce future infestations.

Pea and Bean - weevils are a large family of small active beetles recognized by their elongated snouts.

Both adults and larvae damage plants and fruits. The adults are serious pests biting segments from the edges of leaves. The growing shoots are also attacked and growth can be severely checked.

SPOT THE SIGNS Tell-tale signs are U shaped notches at the edges of leaves, growth is stunted but older plants tend to recover well. Seedlings can be killed by severe attacks.

DEAL WITH THEM Hoeing around plants in April/May time can prevent attack. If you have just sown your seeds cover with a horticultural mesh until the plants are growing strongly and a few inches tall. Protect plants already in growth organically by feeding and mulching the plants. This will help them grow more strongly, healthy strong plants usually can tolerate pea and bean weevil (they just end up chewed edges).

Slugs and snails are every gardener’s nightmare and are quite possibly the biggest pest in the garden or the allotment. They can devastate your crops overnight and reduce even the most hardened gardener to tears!
A good snail and slug management program relies on a combination of methods. The first step is to eliminate, as much as possible, all places where snails or slugs can hide during the day. Boards, stones, debris, weedy areas around tree trunks and dense ground covers such as ivy are ideal sheltering spots.

Try to encourage the friendly predators (see above), copper barriers can be useful for protecting especially susceptible plants, up turned orange or grapefruit shells are a good organic method to try, just empty them regularly, try sprinkling coarse grit in a circle around the plants, beer traps or nematodes which are a living organism and after diluting in water are spread onto your soil, these last about 6 weeks and target the tiny slugs which live under the soil, you can also improve the soil by adding compost. . Snails and slugs favour seedlings and plants with succulent foliage these are the ones which need the most protecting.

Plants that are easy targets include basil, beans, all brassica's (cabbage family), dahlia, delphinium, hosta, lettuce, marigolds, strawberries, and many more. Some varieties have a good resistance to damage, they include begonias, fuchsias, geraniums, impatiens, nasturtiums, as well as plants with highly scented foliage like lavender, rosemary, and sage. Most ornamental woody plants and ornamental grasses are also not seriously affected. If all else fails (and it invariably does) slug pellets are your best bet. Don't feel guilty, we all want to garden organically as much as we can but if you want some crops to show for your hard work then these are the answer.

Whitefly - Adult whiteflies are small, white moth-like insects common in the green house.

Found on in clusters on the underside of leaves a common problem of the Brassica family. Adults and nymphs suck sap mainly on the leaves of tomatoes though they attack other greenhouse plants as well.

SPOT THE SIGNS Leaves turning mottled, pale and curled, foliage and fruit become sticky, black mould grows on this honeydew causing disfiguration on the surface.

DEAL WITH THEM These are not an easy pest to control, hang yellow fly catcher cards above plants. Outdoors especially in the South Whiteflies are troublesome on Brassica's where they attack the edible parts. Cover with a fine netting or fleece when plants are young to avoid attack. Try the organic way of treating them and spray with a garlic and water solution.

Woodlice - These strange hard-skinned creatures can be a pain especially when present in large numbers.
Woodlice are quite harmless and can be beneficial in their proper habitat they breakdown and eat dead vegetation and organic matter in the soil. Woodlice thrive in damp shady parts of the garden. They are nocturnal feeders and cause serious damage in humid conditions under glass, or outside when present in large numbers. They feed on stems leaves and roots.

DEAL WITH THEM You can get a woodlice killer spray but if you want to go down the organic road try some woodlice traps.