WHAT ARE THE NATURAL PREDATORS OF PLANT LICE?




Aphids are probably the most successful - and as such perhaps the most hated - of all the garden pests. Commonly known as ‘plant lice’ or green/black and whitefly in the United Kingdom, aphids can rapidly colonise the soft tissue parts of many ornamental and edible plants reducing their vigour, and productivity. Aphids can also act as a host for transferring viral and bacterial disease.

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With many plant pests you can usually get away with a 'live and let live' attitude as the affect plant - so long as it was reasonably healthy in the first place - will usually grow through any low level damage with no long term effect. Unfortunately when it comes to aphids, if they left to their own devices, the colonised part of the plants will become stunted and withered, and in extreme cases the whole plant may die.

For those wishing to garden organically there are a number of ‘natural sprays’ that you can either ‘buy off the shelf’ or concoct yourself, but there is always the risk of killing off beneficial insects in the process. The truly 'organic way is to call to your plants defences those naturally occurring, native predators who would like nothing more than to get their pincer-like mandibles into a plump, and juicy aphid. The three most commonly occurring native predators are listed below.

LADYBIRDS

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Ladybirds - also known as ‘ladybugs’ – are one of the more easily identifiable aphid predators and can eat over 5000 aphids (or other soft body insects) during their lifetime which is usually about a year. Surprisingly there are about 42 species found in the UK, and although most have the common red and black colouration you will find there are other combinations such as yellow with black spots, and white with black spots.

It is not just the adult ladybird that seems to have an almost insatiable appetite for aphids their larvae will also forage aggressively for aphids.

Adult Ladybirds lay up to 50 yellow Ladybird eggs per day on the undersides of leaves. This equates to up to 1500 eggs in their lifetime although some of the eggs are infertile, thought to be used as a food source for juvenile ladybird larvae.

Most ladybird varieties are excellent predators of pest insects and can usually be found in the garden from March to October.

LACEWINGS

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Lacewings are common insects in British gardens and are easy to recognise by their transparent lace-like wings, which are nearly twice as long as the abdomen. Although adult lacewings feed only on pollen and nectar, their larvae will voraciously attack almost any prey they can fit in their mouths although they seem to have a preference for aphids, other soft-bodied insects and their eggs.
In fact the adults will seek out areas of honey dew - the sugary solution excreted by aphids - in order to find suitable places for laying their eggs.

Lacewing larvae have unusual sucking mouth parts made up of a pair of extremely long, slender and conspicuous mandibles – jaws - that curve forward from the front of the head. These mandibles are tubular in structure, like a pair of hypodermic needles, and are sunk into their preys body and then used to suck out the bodily fluids.

Lacewings can be encouraged to remain in your garden by providing homes for their winter hibernation. That way they will be ready to lay their eggs and help to control your aphids when they emerge from hibernation in the spring.

HOVERFLIES

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Hoverflies are easily recognised by their generally bright colours and hovering ability. They use bright colours so as to mimic wasp colouration to avoid attack by birds and other predators.

While the adult hoverflies will spend much of their life on flowers, feeding on pollen and nectar, their well camouflaged larvae will go largely unnoticed as they crawl over foliage in search of their aphid prey.

Over 250 species have been recorded in the UK, and in fact more than 85 species have been found in a single garden. You can expect to see adult hoverflies between March and early November.

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