Chemical Reaction; HOMES AND PROPERTY

Article excerpt

Byline: GRAHAM RICE

Why use poison when you can get rid of pests with organic sprays or by encouraging ladybirds into your garden, asks Graham Rice

THE days of simply poisoning garden pests are almost over.

As we become more aware of the dangers of garden chemicals, both to our environment and to ourselves, and as government regulations remove the more potent chemicals from the market, we must turn to alternatives if greenfly and other pests are not to smother our every plant.

This is, of course, all to the good. Who could fail to be relieved that the days of DDT poisoning the garden birds and lead, arsenic and nicotine poisoning the gardeners, are no longer with us?

There are still a few chemicals in general use; Provado Vine Weevil Killer deals very effectively with the dreaded vine weevil as well as greenfly and whitefly. But don't use it as a spray, which can be tricky to control.

Instead, water it on to the compost in containers. The plant roots absorb the chemical, which moves around inside the plant, then when pests eat the roots or suck sap from the leaves they get a dose of poison.

You can even use it in the conservatory in this way without the risk of it blowing around the house.

Another recent innovation is the use of organic materials like fatty acids and rape seed oil as pesticides. These come as sprays, but contain none of the poisons (once derived from Second World War nerve gasses) found in many previous products.

Bio Naturen is based on rape seed oil and works by blocking the breathing pores of greenfly, whitefly, red spider mite and other pests. Friendly insects like bees and ladybirds have larger breathing holes so are not harmed.

Fatty acids, sometimes called insecticidal soaps, also work well and don't kill ladybirds. Bio Pest Pistol is the one you're most likely to come across.

This deals with a good range of pests and comes in a ready-to-use spray. Ant and Crawling Insect Killer from Agralan is based on natural oils which cause ants, cockroaches and earwigs to lose moisture from their bodies after contact.

This is for treating the pests themselves and not for spraying the plants on which they may be causing problems.

Biological control, of course, has been the so-called next big thing for years and for many gardeners it will remain so. When it works it's wonderful; it's safe and leaves beneficial insects unharmed, but its effectiveness depends so much on factors such as temperature, timing and care in its application that although many gardeners try, many also fail. An added problem is that it's not cheap. …