Ronéll van Rooyen
The organic vegetable gardener views any sign of insects and rodents as a declaration of war. However, it is interesting to know that some insects keep other insects away from your precious vegetables. This means that you will have to consider your options in deciding what insects you will allow to share your veggies, otherwise you will have to resort to organic spraying.
These are yellow and black flying insects that lay their eggs among colonies of aphids. It looks like extra effort to remove them as well, but when their eggs hatch, the larvae will feed on the aphids.
There are several types, but the most common ones are red and black or just black. They feed on aphids, scale insects, mealy bugs and Australian cicadas but are threatened by ants.
This insect feeds on aphids and grasshoppers. The eggs in the white egg pouch are attached to the stem of a plant, so the hatchlings can start feeding on the aphids right away.
All types of spiders feed on insects and therefore control pests.
Some wasps lay their eggs in the paralysed or dead insect so that food is conveniently available. They feed on several kinds of insects, such as caterpillars, beetles and larger insects.
Other beneficial insects include dung beetles, which play an important role in the veld, robber flies, dragonflies, etc, that use insects as food for themselves or their larvae.
When leaves become discoloured or stems rot or turn black, it is a sign of fungal diseases. These diseases are difficult to control, as is the case in humans. The best way is to use disease-resistant varieties, ensure good drainage and avoid planting vegetables in the same infected soil for two seasons in succession. Chemical sprays may also be used.
Invite birds to your garden
There are several useful insect eaters that can help you combat pests: shrikes, wagtails, swallows, and even chameleons. Bees do not combat pests but are useful for pollination, which is an important factor in producing fruit.
Every insect forms part of a bigger ecosystem, and it is important not to disturb these systems by totally removing certain layers from the food chain. Unfortunately, the vegetable garden and rose trees are a delicious part of the food chain for many insects, but be wise and lure them away to other parts of the garden. Every garden is unique and it is always advisable to gather as much knowledge as possible, even by taking affected leaves to your nursery for advice. Happy gardening!
Christine and Michael Lavelle, 2011, “The organic gardener. How to create flower, vegetable, herb and fruit gardens using completely natural techniques“.
J.G. Simpson, 1995, “Kos uit die tuin. ‘n Suider-Afrikaanse gids om jou eie vrugte, groente en kruie te kweek”.
Margaret Roberts, 2009, Plantmaats.
Dick & James Strawbridge, 2010, “Practical Self-sufficiency. The complete guide to sustainable living“.