6 pointers for responsible use of insecticides

Insecticides are chemicals that kill insects by contact or as they eat the chemical after it has been sprayed on plants. The advice below will help you better understand how to use insecticides safely in your garden.

1. Read the label to make sure you are using an insecticide that is registered to control the insect pest you want to remove and follow the directions carefully.
2. Observe the withholding period – that is, the time lapse between spraying the plant and being able to eat it.
3. Wear protective clothing. Insecticides can be breathed in or absorbed via the skin, so cover your arms and legs and wear gloves, boots, a hat, goggles and a suitable respirator.
4. Be careful when mixing the concentrate. Avoid breathing the fumes or inhaling toxic dust. To avoid any accidental ingestion, wash your hands after use.
5. Don't spray on windy days, if rain is predicted, in very hot weather or in frosty conditions. If you use insecticides to control aphids or thrips, spray late in the day when bees have returned to their hives.
6. Store insecticides in their original containers in a locked cupboard or in a shed that is out of reach of children.

A little understanding about how insecticides work will help you select the most effective, safe and efficient product. The following are some of the main types of insecticide, how they work and their environmental impact.

• Contact insecticides. These must touch the pest to kill it, much like a fly spray. They are fast and effective and usually break down quickly in the environment. However, they can harm beneficial insects.
• Penetrant insecticides. These move a short distance into the plant and are eaten by the pest as it eats the plant. In general, penetrants are safer than contact insecticides as they are less likely to come into contact with beneficial insects. However, they do target insects that feed on plants.
• Systemic insecticides. These move through the vascular system of the plant, protecting the whole plant from pests. Some systemics last for weeks while others can remain in the system for as long as a year. Little is known about what else they may be doing to the environment.
• Broad-spectrum insecticides. These kill a wide range of insects, including beneficial predatory insects. They are marketed as environmentally friendly, but as they kill a wide range of beneficial insects – including bees and wasps – use them with care.
• Selective insecticides. These target a particular pest, leaving other insects unharmed. They are very useful for spot-treating outbreaks of a pest that may quickly spiral out of control.

With responsible use of insecticides, you can keep your garden healthy and free of pests.