The Wildlife-friendly Garden. Michael Chinery

       Hedgehogs Among our most popular garden inhabitants, hedgehogs do good service by getting rid of slugs and snails, although they do destroy the useful earthworms as well.

       Michael Chinery

      A good friend in the garden, this hedgehog is busily polishing off a snail.

       Ladybirds These attractive little beetles eat huge numbers of greenfly and other harmful aphids and are therefore among the gardener’s best friends.

       Centipedes These fast-moving carnivores eat a wide range of other creatures, including slugs, insect grubs and other centipedes, which they kill with powerful venom. On balance, they do more good than harm, and they are certainly not dangerous to us.

       Our foes

       Lily beetles These colourful beetles destroy the leaves and seed capsules of all kinds of lilies. What look like slimy black droppings on the plants are actually the lily beetle grubs which are covered with their own excrement.

       Michael Chinery

      Beautiful, but also beastly, the lily beetle must go if you value your lilies.

       Aphids These tiny bugs occur in huge numbers and they deform many plants by sucking out the sap. They also spread numerous viruses responsible for diseases such as potato leaf roll and various mosaics. There are hundreds of species.

       Michael Chinery

      This apple shoot has been deformed by the piercing beaks of hundreds of sap-sucking aphids.

       Leatherjackets These rather featureless grey creatures are the grubs of crane-flies or daddy-long-legs. They live in the soil, especially under lawns and flower beds, and destroy the roots.

       Cabbage white caterpillars The black and yellow caterpillars are the larvae of the large white butterfly. Living in large clusters, they can quickly reduce a cabbage leaf to just a skeleton, and they contaminate the rest of the plant with an unpleasant smell.

       Michael Chinery

      Caterpillars of the large white butterfly here surround a solitary caterpillar of the small white. Both species are major pests of cabbages and other brassicas.

       Slugs Perhaps the most hated of all our garden residents, the slugs nibble their way through our flowers and vegetables with equal enthusiasm. But not all slugs are pests: some of them prefer rotting leaves and fungi (see here).

       Michael Chinery

      One of the worst of the gardener’s foes: the netted slug is the one we usually find in our lettuces.

      Pest control

      Gardening will always be a competition, with the gardener pitting his or her wits against an assortment of uninvited guests which are doing their best to damage the plants. Although you may have to get tough from time to time, it need not be all-out war. Live and let live is always a good motto for the gardener.

       Avoid chemicals

      One can buy chemicals, i.e. poison, to control just about every garden visitor, but they have many drawbacks. There is always a risk of killing useful or harmless creatures as well as pests. Killing useful creatures, such as ladybirds, may actually lead to an increase in the garden’s aphid population and a tendency to use ever increasing doses of insecticide. Although most modern pesticides break down rapidly in the soil, heavy applications may lead to a build-up of residues that can damage the soil and enter the food chains, where they can have far-reaching and surprising effects. Killing harmless creatures does have a knock-on effect by denying birds and other animals their natural food, so your garden will be much less interesting. The true wildlife gardener uses non-poisonous means to discourage or get rid of pests. Aphids, for example, can usually be controlled simply by squashing them with your fingers.

       Michael Chinery

      Re-cycling the empties: this lacewing larva, pictured with its jaws plunged into an aphid, camouflages itself by piling the empty skins of its victims on its back.

       Cultural control

      Adjusting the way you grow things, or even what you grow, can make your garden less attractive to pests. Most weeds, for example, can be eliminated by spreading a layer of chipped bark or compost over the garden. You can try growing red cabbage instead of the traditional green varieties: this may not deter the cabbage white caterpillars, but at least you can see them more easily and remove them before they do the damage!

      Companion planting or inter-planting is often used to reduce damage by pests. Planting onions and carrots close together works well because the smell of the carrots deters or confuses the damaging onion-fly, and the smell of the onions discourages the carrot-fly. Roses or other flowers planted at the ends of vegetable rows attract hover-flies, which may lay eggs on aphid-infested crops. Some hover-fly larvae can demolish the aphids at a rate of one every minute!

      Doing nothing and allowing nature’s web to keep the pests in check is probably the best method of all. Surely losing a few plants to beetles and caterpillars is a price well worth paying for a garden which is teeming with wildlife and with no risk of poisoning yourself or your family?

       BIOLOGICAL CONTROL

      Biological control, which uses natural enemies to keep pests in check, can be wonderfully effective. Introducing ladybirds and their larvae to your garden, for example, can wipe out an infestation of aphids in days. A single ladybird larva may eat 500 aphids in its three-week development. Green lacewings (see here for stockists) do a good job on summer populations of aphids, and are useful in greenhouses throughout the year.

      Biological control of slugs, which are surely at the top of most gardeners’ hit-lists, can now be achieved simply by using a minute parasitic worm called Plasmarhabditis hermaphrodita. Available through good garden centres and other suppliers (see here), the worms seek out slugs and bore their way in. They multiply