A healthy garden with a wide range of plants will attract many forms of wildlife including natural predators such as birds, ladybirds, frogs and toads. Their presence will help maintain a naturally balanced environment and the need for artificial pest control will be kept to the minimum. Regular hoeing between plants will not only control annual weeds, but bring many pests to the surface where birds can deal with them. There are products available whose effect is specifically directed to a single problem or plant, or that are non-persistent – they remain active only for a short period. Many of these are derived from plants, and have a less damaging effect on the environment as a whole than all-embracing chemical fertilisers, pesticides and fungicides.

ANTHOCORIS BUGS are 1/6 in long and black-brown. They often gather on willow catkins, and eat scale insects, capsid bugs, caterpillars and midges.

BIRDS may reduce your crop of autumn berries, but will help control grubs, snails, slugs, caterpillars and aphids.

CENTIPIDES – sometimes shelter beneath ground cover during the day, but at night prey upon many small insects and slugs.

COPPER FUNGICIDES, including Bordeaux and Burgundy mixtures, remain effective for several weeks as a control against mildews and blights, but appear to be harmless to many beneficial insects.

DERRIS is a non-persistent plant extract used to fight caterpillars and aphids. It is toxic to the eggs of some ladybirds and adult lacewings, and harmful to fish, so should be used with discretion.

FROGS AND TOADS will keep the slug population at bay, and also eat woodlice. A garden pond will provide breeding facilities for them.

GROUND BEETLES like damp, sheltered conditions during the day, but emerge at night to hunt out eelworms, leather-jackets, larvae and insect eggs.

HEDGEHOGS will leave their shelter beneath hedges or a pile of logs at night to forage for slugs, cutworms, wireworms, woodlice and millipedes.

HOVER FLIES are thin, wasp-like insects, and lay their eggs on aphid colonies. The larvae have voracious appetites: one larva kept in captivity was recorded as eating around 900 aphids in its lifetime. French marigolds (Tagetes and Calendula species) attract hover flies.

INSECTICIDAL SOAP is a potassium-based product effective for only one day, but a direct hit kills aphids, red spider mites, white flies, scale insects and mealy bugs.

LACEWINGS produce larvae which suck the body fluids from aphids. If all the larvae produced from just one female survived, they could consume 20 million aphids in a season.

LADYBIRDS, in both adult and larval stages, feed on aphids, scale insects, mealy bugs, thrips and mites.

PYRETHRUM and ROTENONE should be carefully directed at pests such as aphids. Extracted from the flowers of certain chrysanthemum species, they are harmful to some beneficial insects, but are non-persistent and harmless to animals.

QUASSIA controls small caterpillars and aphids, but does not harm bees, ladybirds or the anthcoris bug. It is sold in chip form, simmered with water and strained before use.

See also:
A directory of common garden pests and diseases