Beneficial Insects
Part of living an organic lifestyle is about learning not to rely on chemicals as a means of protecting ourselves and our crops from so-called pests.
On a large economic scale, pests such as caterpillers,aphids and scale can ruin crops, but by encouraging beneficial insects, birds and small creatures such as frogs and lizards, we can attain a balance.
Pests become a nuisance because they are fastbreeding, and they can quickly take advantage of an out of balance system. They can be a sign that plant and soil-life is not optimal, and that the plant may be weak and stressed.
They also provide an ample supply of small, easy-to-catch food for many small creatures. Spiders, wasps, frogs, lizards and birds all benefit from infestations of what we call pests, and they call dinner.
Insect pests tend to come in flushes, at least that's how it looks when there's already lots of them when you notice. When this happens the temptation is to spray but if you allow the infestation to continue a little longer, the approptiate beneficial insects will come along and clean-up for you.
Once the balance is established there's much less worry about other things eating your veges.
The longer it is since chemicals were used the more diversity and more beneficials there will be.
BETTER KNOWN BENEFICIALS.
LADYBIRDS and their larvae eat aphids, mealy bugs, mites, thrips, moth eggs and other small pests. They can multiply rapidly given the opportunity (ie an aphid colony). Yellow clusters of eggs appear on the host plants. Before long the little spiny-looking black-and-white larvae are off and growing fast on a feast of aphids.
DRAGONFLIES eat mosquito larva during their larval stage, which is spent in water (and is best survived with no hungry, large-mouthed goldfish). As adults, a large variety of flying insects are caught in flight, a fine skill indeed.
HOVERFLIES, as adults and larvae attack aphids, mites, scale and young caterpillers. They are attracted by many small flowers such as Allysum, St Anne's lace, tansy, yarrow and many others.
PARASITIC FLIES AND WASPS
Now we move onto some lesser known parasitic wasps and flies. Wasps bear a resemblance to ants, to which they are related. They are smaller, skinnier and more elongated than paper wasps, generally, and some are very small, indeed.
- Aphelinid wasps - these are tiny and lay their eggs in (yes, in) aphids. They can sometimes be seen in a busy aphid colony.
- Trichogramma wasps - parasitize many kinds of moth eggs (by laying their eggs inside them), and other insects. These are very small and very helpful.
- Paper wasps and mud daubers- put insects, spiders and caterpillers in with their larva before sealing them in.
- Chalcid wasps - very, very small and very sensitive to pesticides. They attack scale, flies, aphids, leafhoppers, whitefly, beetles, mealy bugs and caterpillers.
- Tachinid flies - look quite similar to house or blow flies, but more stout and usually more hairy. Tachinids attack larva of many insects and are economically significant in protecting organic crops.
- Ichneumonid wasps - these are great killers of caterpillers, even able with its long ovipositor (egg-laying tube) to put eggs into a caterpiller that is within a tree's bark. Their action prevents many caterpillers from reaching maturity.
- Braconid wasps - attack caterpillers by laying eggs on or inside them. They can be small insects and 100 or more grubs can be found inside one caterpiller. Once emerged the grubs make a coccoon nearby to finish their metamorphosis. Limp, empty looking caterpillers are a good sign that you have parasitic wasps in your garden.
So you see, fly spray doesn't just kill flies, it might kill your veges too, if you've accidentally poison your beneficial insects.
Happy insect-watching!
Vicki B