Safer Pest Control

Looking after your plants properly is the best possible way of avoiding trouble with pests and disease. Healthy, well cared for plants rarely suffer serious attacks, and any mild infestation is usually shrugged off easily by a thriving plant.

More and more people now feel that to use strong chemicals unnecessarily is a bad thing, partly because they often kill off beneficial insects as well as the

unwanted pests and also because many common pests are developing an immunity to the pesticides being used. Indoor gardeners are rightly veering away from using strong insecticides in the home (many sprays really should only be used out of doors), and are finding less drastic treatment.

After looking after your plants properly (seeing that they are in the right light and temperature, receive sensible watering and feeding, etc) the best way to control an attack is to act as soon as possible. This will mean frequent and close looks to spot the first signs of pests or disease. This need not prove a chore since looking at and caring for plants is, for most of us, a pleasure.mist spraying pest control

Examine particularly the soft growing tips, flower buds and soft flowerstalks. A number of pests hide on the undersides of the leaves, so turn foliage over periodically to check for young aphids, scale insects and whitefly. Look in leaf axils for mealy bugs and scale insects and, when repotting, look for soil-borne pests. The odd pest can easily be picked off by hand and destroyed, but remember that most pests increase very rapidly and evidence of just one adult usually implies that there are several offspring about, which may be too small to see. If you spot an adult keep a keen eye open for developing young. Pests can often be flushed off leaves and stems (both indoors and out) by nothing more deadly than a strong jet of plain water from a mist sprayer. The addition of a few drops of liquid soap to this water will greatly increase efficiency. Spray all parts of the plant, including under the leaves.

When it is absolutely necessary to use an insecticide, always read the label carefully and stick rigidly to the instructions. Always ensure that the container and the sprayer are kept away from and out of the reach of children. Always dilute to the recommended strength — too strong a solution may burn the plant, too weak and the pests may develop an immunity to the chemical.

Since 1986 new statutory regulations about the labelling and packaging of insecticides and fungicides have come into effect. These apply to products that are available to amateur gardeners. No new products can be introduced to the market until they have been approved by an independent body and exact instructions as to their use must be clearly stated on the packaging.

Common plant pest guide

Symptoms and cause

Aphids — Weak growth with a sticky substance (honeydew) on leaves.

Black vine weevils — Ragged holes in leaves Beetles may appear at night.

Mealy bugs — Cottony blobs in leaf axils or stems occur in dry conditions.

Red spider mites — Fine webbing on leaf axils and tiny spots on leaves.

Treatment

Dislodge aphids with a spray or with a jet of water mixed with liquid soap.

Pick off pests and repot plant. If severe, treat with HCH dust.

Remove with a small brush or cotton wool swab dipped in diluted methylated spirits.

Mist spray often. You can use predatory mites to control them biologically.

Scale insects — Tiny brown, shell-like bumps on leaves or stems.

Rub away gently with a cotton wool swab dipped in dilute methylated spirits.

Springtails — Minute white grubs hop about on compost surface when disturbed.

Improved drainage and a little added lime should control these pests.

Snails — Large, uneven holes in leaves or flowers, usually on outdoor plants.

Distract with lettuce, or trap in a saucer of beer. Use slug pellets with care.

Whitefly — Minute white flies on leaves. They may promote sooty mould.

You may need to use a contact insecticide, as whitefly are hard to remove.

Further pest control

Outdoor pests

During the warmer summer months pests increase at an alarming rate. Out of doors their number and their rate of increase are greatly reduced by cooler weather, but all are capable of over-wintering by hibernating or by laying eggs which survive all but the very worst winters. Hatching out of eggs can take place very early in spring.

Encourage insects such as ladybirds and lacewings to the patio or window-box, as they consume large quantities of aphids. Hedgehogs feed on slugs and snails, and there are many other useful insects about that do good.

Indoor pests

Under warm indoor conditions many of the common pests carry on just the same during the winter months, and regular inspections are necessary.

Frequent mist spraying and a high level of humidity will totally discourage an attack by red spider mite.

Pests that cling firmly to their hosts must be dislodged with something more drastic than a jet of water. The odd adult scale insect should be picked off with a toothpick and the stem or leaf wiped with a cottonwool swab or artist’s paintbrush dipped in diluted methylated spirits. This should finish off the tiny but active ‘crawlers’ (the young) that shelter under the protective shells of the immobile parents. Mealy bugs are protected from both water and a liquid insecticide by their woolly and water-shedding mealy wrappings. Pick off any you see with a toothpick and dab with diluted methylated spirits.

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