Some garden pests have a distinctly weird appearance. Scales are a good example. The actual pests are rarely seen, but the dome-shaped scales under which many species live and feed stand out clearly.
We see these scales lined up along the midribs of citrus and other leaves, often accompanied by masses of sooty mould that disfigures leaves and fruit.
Good control can be achieved by spraying with commercial pest oil. A cheap, homemade scale killer is made by blending together a cup each of cooking oil and water plus a few drops of washing detergent.
The resultant white oil emulsion can be kept in a screw-top jar. To use, dilute one part of homemade white oil to 20 parts water and spray under and over infested foliage.
The strange-looking cottony-cushion scale attacks the foliage of apple and fig trees, rose plants, citruses and pittosporum hedges. The sap-sucking pests are covered with a white, waxy material, making infested plants look as if they are covered with tiny blobs of cotton wool.
If few scales are present, any infested leaves can simply be picked off and destroyed. For more serious attacks, two or three sprays of diluted homemade white emulsion at four- day intervals should do the trick.
Almost identical is the white, fluffy hydrangea scale. It often attacks congested, unpruned hydrangeas under stress due to lack of water or infertile soil.
The scales often cover the undersides of leaves and can also be seen dotted over the bark of congested branches. Hard pruning in late autumn opens up bushes by cutting out all old exhausted branches almost to the ground.
While oil sprays can finish off any remaining scales, feeding pelletised poultry manure and regular summer watering will keep these pests at bay.
Woolly aphids attack apple trees, causing the bark to form unsightly calluses where they have been feeding. Infested branches look as though they are forming patches of white, woolly fleece.
These pests overwinter by becoming deeply embedded in pruning wounds or areas of damaged bark. They can be seen massed together just above the ground during winter.
Excellent control can be achieved by painting woolly aphid clusters with methylated spirit to produce an instant kill.
During winter, the same treatment can be applied around the bases of apple trees.
If dabbed into cracks, crevices and beneath loose bark, methylated spirits will also destroy overwintering codling-moth grub cocoons.
A really unpleasant vegetable garden pest is the green vegetable bug, also called the stink bug.
They are bright green and shield-shaped and operate during summer feeding off beans, pumpkins, tomatoes, sweet corn and other vegetables.
They are often seen on ripening tomatoes which they spoil by penetrating skins to leave a pale halo of discoloured blotches.
Vegetable bugs mate by sticking their backsides together and can be seen trundling around in pairs as the female swells with fertile eggs.
When disturbed or squashed they give off a strong, unpleasant smell.
I squash them between folded leaves or shake clusters of bugs into a bucket containing a little water topped with a few drops of mower fuel.
Harlequin bugs, which are black with an orange mark just behind the tiny head, also emit the same foul smell if squashed and mate in the same back-to-back manner.
They multiply rapidly and when infestations are severe there can be colonies of several thousand occupying and destroying small gardens.
They tend to cluster in the morning sun, young and old together, favouring wooden fences, tree trunks or sheds.
This daily congregation allows entire harlequin bug colonies to be sprayed with an extra-strong solution of laundry detergent. This stuff dissolves their protective, water-repellent waxy coats. It then penetrates breathing tubes at the sides of their bodies, killing them instantly.
The most effective way of keeping most garden pests under control is by regular pruning and weeding to eliminate breeding zones.
Best of all is to develop a natural balance of living things in a garden by avoiding all poisons and life-disrupting chemicals.