ORGANIC CONTROL OF AHPIDS ON ROSES



Is there anything more perfectly English than the unblemished blooms of a traditional Tea rose? The fact that their roots (historical that is) originate far on the other side of the world is neither here nor there as without their quintessential show and fragrance how you can possibly make an Englishman’s home his garden?

Beneath the surface of its skin deep beauty, a secret struggle of chemical and biological warfare rages, and much like any other arms race the stakes just keep getting higher.

As more of our garden pests become resistance to insecticidal chemicals we are force to develop newer and more effective replacements, but at what cost? If this cycle of resistance and development isn’t broken then it’s the environment that pays while big chemical manufacturers line their pockets by feeding off our weakness for perfection.

There are numerous enemies that we must defend our beloved blooms from, but one rises above all the others to give us our greatest threat. Stealthily they attack, confusing us with their many faces, but we will name them one by one, Blackfly, greenfly, and whitefly.

Camouflaged by colour, they cannot hide the truth that they are all related to that same heinous family - the aphids! Their destructive hypodermic mouth parts drain the plants of their strength as well as disfiguring soft new shoots. Even more sinister is that they too trade in biological warfare by transferring viruses from plant to plant in their saliva. This is the plant world’s despicable equivalent to sharing dirty needles.

Perhaps we should look to Ghandi for inspiration and try to find a more a peaceful solution that doesn’t involve the wholesale and indiscriminate destruction of other beneficial insects. We could use ‘organic’ insecticides such as pyrethrum derivatives or fatty acid sprays (but please avoid the flowers), but that’s just what they would expect us to do. There is another way, a two pronged attack using companion planting and natural predators.

COMPANION PLANTING

This can work in two ways.

The companion plant itself can discourage your rose pests. Planting garlic - or catmint in among your rose displays is a tried and tested method of deterring aphids.

It’s believed that essentials oils released from the companion plants help to mask the Roses own fragrance making it difficult for aphids to identify their host plants, but don’t worry as your nose won’t be sensitive enough to tell the difference, unless you crush the leaves first! Click here to learn How to Grow Garlic.

Using the right companion plants can positively encourage aphid predators. These include marigolds, cosmos, sunflowers, fennel, dill, and yarrow. These will attract deadly battle groups of damselfly, hoverflies, lacewings, ladybirds, whitefly and parasitic wasps to your defence. With the exception of cosmos it will also provide you with a nice selection of home grown, dig for victory, herbs.

NATURAL PREDITORS

Without understanding the life cycles of these natural predators you can never expect to get the best out of them. By creating the right habitats in our garden, we can help to promote and encourage each of their life cycles.

This can be achieved by providing log piles that, when allowed to rot naturally, will create a fantastic haven for them in the garden. Although not normally regarded as an aspirational want, the common nettle is also a fantastic plant for encouraging insects into the garden, supporting over 40 species of insect including some of our most beautiful butterflies.

LADYBIRDS

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

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 mouthparts 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

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.

Now that the battle plans are in place we can look towards the new rose planting season with a brave new hope. Good luck and we hope to see you on the other side.
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