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Maintaining Bio-Diversity by Avoiding Artificial Pesticides

From Derek Solomon’s Gardening With Birds in Zimbabwe, published by Birds of a Feather (Pty)Ltd, Harare, 1992

A large proportion of the birds which live and, hopefully, breed in our gardens are insect eaters, and rely on this source of food to survive and feed to their young. Many seed-eaters rear their nestlings on insects in the early stages because their normal seed diet is not rich enough in protein for the young birds. Nectar-feeders also need to supplement their diet with insects in order to survive.

Despite this we are inclined to spray potent insecticides all over the garden without any thought about the effects this may have on the wildlife within the area.

White-eyes glean aphids off our plants, thrushes eat snails, hoopoes and other birds feed on worms on the lawn and cuckoos consume large quantities of hairy caterpillars. However, they do not know if you have just sprayed these insects with a highly toxic pesticide. Therefore


If spraying is necessary, use a less toxic material. Remember that the main breeding season is from late August to early October and this is when the birds will be most susceptible to use of pesticides in the garden.


There are several natural pesticides which can be used most effectively around the garden. They can be applied with a sprayer or watering can or by dipping leafy twigs in the solution and sprinkling this on to the plants. All food treated with natural pesticides should be washed in clean water before use. Remember that all of these sprays are toxic and should be kept away from children and pets.

Chillies or hot peppers

Boil a bowlful (0.5 kg) thinly sliced ripe chilli peppers in 3 litres water for 15 – 20 minutes. Add 30 grams soap and stir to make solution soapy (so that it will adhere to the plants). Add another 3 litres water and allow to cool, then strain. Use on vegetable gardens against caterpillars, aphids, flies, ants, mealy bugs and other pests. Apply once per week if there is no rain or two to three times per week if it rains.


Crumble l kg fresh leaves, let them soak in 10 litres water with 2 tablespoonfuls of paraffin. Let this stand for 3 hours, then filter. Use on all plants against a variety of pests.


Boil a double handful of dry leaves (200g) with some ground leaves (snuff) or cigarette ends in 3 – 4 litres of water for 15 – 20 minutes. Add 30g soap and stir while letting solution cool. Add 3 – 4 more litres water. Filter through a light cloth. Spray on maize or sorghum to kill stem borers and on other plants infested with caterpillars, aphids, flies, mites or scale.

Left-overs from tobacco drying floors and packing companies make an excellent insecticide when spread onto the lawn.


Use fresh (but not hot) ash from cooking fires. Sprinkle handfuls of ash around seedlings as soon as they sprout to repel cutworms. Replace after each rain.


An excellent spray for control of aphids can be made with any combination of the following herbs: tansy, feverfew, wormwood, rue, lavender, rosemary, sage, basil, marigold, elder, rhubarb.

Chop up sufficient leaves to fill half a bucket and pour boiling water over the mixture until the bucket is full. Leave overnight and then strain off the leaves. Add half a cup of washing powder or dishwashing liquid (preferably bio-degradable). Bottle the liquid and spray when required.

The left-over leaves can be dried and packed into sachets and used in cupboards to deter ants and other pests.

Washing-up liquid

Put a squirt of washing up liquid into a bowl of water and swirl it around to make foam. Scoop foam up with your hand and spread it over aphids clinging to, for example, rose buds.


These are just a few of the easily obtained natural pesticides. They can be used alongside the idea of companion planting (planting plants that insects do not like, such as marigolds, alongside plants they adore munching on, such as roses).

Derek Solomon
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