The aim of organic pest control is to reduce damage to an acceptable minimum. It is neither possible nor desirable to eliminate all pests completely from the garden.

Natural balance

If the right conditions are created in the garden, there will be a host of useful predators and parasites available to control pests. These conditions are habitat (somewhere to live) and food (pests or other food used during different times of the predators' life-cycle). The best way to maintain the conditions required for a range of useful organisms in the garden is to have a diversity of plants growing in the garden and to avoid the temptation to try and eliminate all pests.

Some commonly found useful garden predators and parasites are birds, lizards, frogs, spiders, ladybirds, hover flies, lacewings, dragon flies, praying mantis, centipedes, parasitic wasps, predator mites.

Soil Conditions

Improving soil quality can reduce the occurrence of pest and disease infestation in the garden. Plants grown in good healthy soil will themselves be healthy. Healthy plants are disease resistant. Fungi and moulds in healthy soil produce natural antibiotics, cleansing the soil and aiding plants' disease resistance. Unhealthy plants, including plants raised on artificial fertilisers, attract pests. Healthy plants will resist pest attack and outgrow pest damage.

Organic sprays and dusts

Materials with natural insecticidal properties, which quickly break down and do not cause contamination may be used to kill garden pests. They will also kill many useful organisms so they are to be used as a last resort only.

Pyrethrum - The dried flower heads of the pyrethrum daisy are used to make an insecticide spray. The spray, though non-residual, is quite strong and should be used with caution.

Neem - Oil extracted from the Neem tree has insecticidal, fungicidal and antiseptic properties.

Rotenone - A powder derived from the roots of various tropical plants. Kills insects and fish. Do not use near water. If used in excess, rotenone will kill earthworms. Also known as derris.

Quassia - The wood and bark of the Quassia tree, from South America, is a mild insecticide. Quassia chips can be kept in long term storage with little loss of potency.

Bacillus thuringeinsis - A micro-organism that acts as a stomach poison for caterpillars. Sold under the name 'Dipel'.

Sulphur - A yellow mineral used as a powder. Fungicide and miticide. May damage tender plants.

White oil - Mineral oil used to control scale. Acceptable for occasional use.

Repellent sprays
Home made repellent sprays are prepared as per herb tea then sprayed to protect vulnerable plants. Some have mild insecticidal properties. They include garlic, rhubarb, cloves, aniseed, sage, camphor, chillies, chives, onion, feverfew, wormwood, tansy. Mixing soap with a spray improves its wetting ability and increases the insecticidal effect.