Poison is poison

Although assassin bugs are themselves eaten by birds, like true assassins they ambush other insects.

Many gardening articles in various magazines unfortunately at times create the impression that so-called environmentally-friendly poisons are okay to use in the garden. Such articles are often motivated by the advertising revenue that poisons generate. But the authors usually seem to be totally ignorant of the fact that, whilst poisons may be needed in agriculture, “pests” can most definitely be controlled without resorting to any kind of pesticides whatsoever in the average urban garden.

The majority of birders are aware that insects are an essential food source for most garden birds and their fledglings, including the fruit- and nectar-eaters. If you don’t have a garden rich in insect life, your variety of bird species and other small wildlife will most likely remain low, unless there is a good insect food source nearby.

There are many natural “controllers” of pests in the garden in the form of predators such as spiders, mantids, centipedes and a host of other small creatures. However, when poison, even the misnamed eco-friendly poison, is used these predators are destroyed along with the pests. Because predators breed more slowly than their prey, the pests recover quickly and now have fewer predators to keep them in check, so a population explosion occurs. The horrified gardener resorts to even more insecticide and quite predictably, through the same sequence, the last few predators in the vicinity are eliminated and the pests multiply uncontrollably.

Suspended by their front legs, usually in thick vegetation or long grass, hangingflies catch passing insects with their other legs.

Preying mantids devour a large number of insects in relation to their size.

A vicious cycle is created, so that the more poison you use, the more pests you’ll have and the more poison you’ll need. Of course, none of this is mentioned on the poison packet. No matter how much poison you use, you will never eliminate all the pests. There will always be more to invade your predator-free garden almost immediately from elsewhere.

Even the “friendliest” of remedies will harm the small predators, usually located close to, or often among, the areas “infected” by their prey. For example, the larvae of hover flies are often found among aphids, of which they consume large quantities. If you have a garden where all the predators have been eliminated, then there will be a frustrating period waiting for them to return after you stop using poisons. But for the patient environmentally-friendly gardener, the natural balance will eventually be restored and major infestations of pests will be short-lived.

Because we have not used any poisons whatsoever in our Durban garden, not even the supposed environmentally-friendly ones, for over three decades, we have an abundance of predatory insects. These, together with the birds, ensure that we have no problem at all with the usual garden pests such as aphids, ants, cutworms, crickets, caterpillars, etc. Some imported pests, like mealy bugs, are promptly removed by hand, but absolutely no indigenous creature is ever killed.

Robber flies catch their food in flight and will attack insects much larger than themselves.

Photo: P. Vos

Indigenous vegetation is optimal in providing for garden wildlife and in general local plants will not be destroyed by indigenous insects as they evolved together. Planting FOR the insects is a totally different mind-set of using poisons and not only gives watching garden wildlife another dimension, but also creates even more bird buffets.

These principles are well described in our books Bring Nature Back to your Garden and Bring Butterflies Back to your Garden. The last-mentioned could easily have been named Bring Birds Back to your Garden because, where butterflies and their larvae (caterpillars) go, birds will soon follow. But if most gardeners, or even only most birders, followed our example then it would result in a drastic reduction in profit for the poison manufacturers and their vendors. So they are duty bound to defend their products.

Further reading

These books are generally available at most bookstores and can both be ordered directly from the Flora & Fauna Publications Trust.

About the authors

Charles Botha is a semi-retired businessman and, although he has always been interested in plants and wildlife, his only qualification in this field is an LBE (Learned By Experience). He is past chairman of the KwaZulu-Natal Region of the Wildlife and Environment Society of SA, and a life member of both this organisation and the Botanical Society of SA as well as a member of the Lepidopterists’ Society of Africa.

Julia Botha holds BPharm and PhD degrees and is an Emeritus Professor of Pharmacology at the University of KwaZulu-Natal. She is past Chairperson of the University’s Environmental Committee.

Website: Flora & Fauna Publications Trust