Beneficial Insects

Most gardeners (especially non-organic gardeners) regard ALL insects as pests and use pesticides as a matter of precaution throughout the year.

Although some pesticides are stated to be harmful to the specific pest that they are intended for and will not harm other insects, there is no guarantee of this. Some pesticides kill indiscriminately and will kill all insects that they come into contact with.

Many of these insects that are killed, are actually BENEFICIAL in our gardens. Most Flower, Vegetable and herb plants are pollinated by insects. By killing these beneficial insects as well as what we regard as pests, aphids for example, we are actually reducing the productivity of our gardens.

A lot of these insects, if left to their own devices, will help the gardener, not only by pollinated flowers but by reducing the number of pests in the garden.

Invite beneficial insects to your garden by growing plants and flowers which provide food and a home for them.

Many of the insects which you will utilise don't actually do any control work themselves. They spend their lives enjoying the nectar and pollen from your flowers, and creating offspring. It is the larvae stage of these offspring which does the actual hunting and eating of the harmful insects.

Some of these insects can now actually be purchased for use against pest infestations.

One thing to remember though, if you have made the decision to utilise beneficial insects to help you with your pest control in your garden, keep in mind that insecticides are no longer an appropriate option. Pesticides will kill the beneficial insects as well as the pests.

Read on and find out what you should be encouraging into your garden and what insects you can purchase and their uses.

Natural Beneficial Insects

Ground Beetles - There are many different species of ground beetle, most of them are beneficial to the gardener. Beetles will kill and eat slugs and caterpillars. They feed mainly at night and during the day they hide to keep away from their own enemies such as birds. They can eat a considerable number of slugs in one night. Provide hiding places for them by planting plenty of ground cover plants or by proving a few logs or a small pile of rocks here and there where they can find a moist hiding place.

Ladybirds - (Ladybird beetles) feed on aphids, whiteflies, and mites, as well as many other soft-bodied insects and their eggs. There are more than a hundred ladybird species. Each adult may consume as many as 5,000 aphids during their adult life. When mature, each female will begin to lay as many as 3-4 dozen eggs each day. Upon hatching, each ladybird larvae will begin consuming 50 aphids each of the 21 days until they reach the adult stage, when the cycle begins again. That's a lot of aphids and undesirables removed from your plants.

Green lacewings - The larvae will eat spider mites, thrips, leafhoppers, whiteflies and caterpillar eggs. .The larvae will feed for only 2 or 3 weeks before becoming adults. Build a home for the adult Lacewings to hibernate in over the winter period. (Plan to build a Lacewing house)

Hoverflies - The hoverflies need to feed on the pollen of plants such as the Poached Egg Plant (Limanthes douglasii) before laying their eggs in a colony of Aphids. The larvae, when they hatch, feed on the Aphids, eating as many as 100 a day.

Commercial Predatory Insects

Phytoseiulus persimilis - This is a very big name for such a little insect. It is in fact a microscopic mite that preys on Red spider mites. Only for use in a greenhouse.

Encarsia formosa - This little parasitic wasp, harmless to humans, is deadly to Whitefly. It injects it's eggs into the bodies of the whitefly and as the larvae form, they eat the whitefly from the inside. Unfortunately it is only suitable for use in a greenhouse.

Aphidius matricariae - This is another parasitic wasp that preys on Aphids in the same way. Only for greenhouse use.

Stienernema bibionis - is a parasitic nematode that preys on Vine Weevils. Applied in a water solution.

Verticilium lecanii - This is a fungus that is sprayed to control Aphids. Only for greenhouse use.

Bacillus thuringiensis - This is a parasitic bacterium that is effective against some caterpillars, particularly the cabbage white caterpillar.