Whether you grow a few herbs on the kitchen windowsill or you’ve got a small garden or an allotment, you are sure to have had the pleasure of meeting Mr Greenfly and his sap-sucking family. Your best weapon against these little bugs is vigilance. Get to know your plants and gardens and check them regularly for signs of pests. In warm environments such as a kitchen or greenhouse a few overwintering aphids can breed very quickly to become a problem.
Watch out for early signs of aphids. As the weather starts to warm up they start to appear and to breed vigorously feasting on newly emerging shoots of their favourite plants.
If you can spot them early and reduce them in their numbers you can limit the extent of their presence within the whole garden. Bear in mind though that in the garden these tiny sap-suckers are a vital ingredient in the diet of many birds and also beneficial insects such as ladybirds, hoverflies and lacewings and their young.
Manual control is a good weapon. Check susceptible plants regularly and squash any aphids that are seen. Pick off heavily infested shoots and leaves and drop them into a bucket of soapy water.
Where there is a heavy infestation on a rose bush or other shrub outside, you can use a strong jet of water from a hose to dislodge aphids. This is best performed early in the day to allow the plants to dry more rapidly and avoid conditions conducive for fungal diseases to attack.
If the problem is widespread and you need a helping hand then use a suitable insecticide. Choose those that have reduced impact on the environment such as insecticidal soap and rapeseed oil. These are available widely available from garden centres. They are contact insecticides that kill on contact with the insect. For best results, drench the aphids thoroughly using a powerful sprayer. There is no benefit in spraying parts of the plant not infected. Sprays approved for use in the organic garden can still be harmful to beneficial insects, they cannot tell the difference, so only use them as a last resort. Spray flowering crops at dusk when bees are not active and avoid systemic insecticides that persist in the plant.
Natural ways to control aphids
- Make sure growing conditions are favourable for sturdy plant growth. Avoid using nitrogen-rich fertilisers: these can encourage excessive soft, sappy plant growth that attracts aphids.
- Make your garden wildlife friendly to encourage a range of beneficial insects and creatures. Avoid using harmful sprays and provide suitable wildlife habitats such as hedges, woodpiles, ponds and nettle beds. There are many creatures that feed on aphids, including wasps, birds, insect larvae, earwigs and bats.
- You can also choose to grow flowers that attract hoverflies, lacewings and ladybirds. These beneficial insects prefer small, simple flowers such as members of the Umbelliferae and Compositae families, as well as the poached egg plant (Limnanthes douglasii), Convolvulus tricolor and buckwheat.
- Remember that these natural pest control allies do actually need a supply of aphids to survive, so leave some where they are not a particular problem. A patch of nettles can be a good source of nettle aphids.