Last Updated on December 21, 2023 by the Dobies Horticultural TeamAt this time of year aphids are beginning to rampage. These small, pear-shaped insects like soft new growth on trees, shrubs, perennials, climbers, fruit, annuals and veg. In other words – they’ll eat most things.
Aphids feed by sucking the sap from plants which weakens them and can cause them to die. Although most aphids are visible to the naked eye you’ll know they are around when you spot deformed and distorted leaves.
Aphids also spread virus diseases and secrete a sticky substance on stems and leaves called honeydew. This in turn may be colonised by an unwelcome black fungus called sooty mould.
The term “aphid” includes greenfly, blackfly and other relatives with some even being a pinkish-red. These soft-bodied creatures will multiply quickly with a female giving birth when just a few days old. Aphids may be small but they are a serious pest in the garden!
Strong vigorous plants cope best with aphids so making sure your plants are growing well. This means being in the right soil and aspect and being fed and watered as their type requires.
Insecticides such as Bio Kill are effective in ridding plants of aphids. As with all insecticides do follow the instructions carefully. Also, store them out of reach of both 2 and 4 legged small family members. Please don’t spray Bio Kill or any other insecticide on plants in flower as you may harm beneficial pollinating insects.
Organic controls include spraying with soapy water or alcohol solution. Possibly the most rewarding method is to lightly spray with water and then to gently rub the leaves and stems between your fingers. Wearing gloves will prevent your hands turning an alien green colour.
Companion planting will certainly help with nasturtiums possibly being the most often used. French marigolds however are particularly useful in aphid control as they attract hoverflies who in turn feast on the aphids.
Certain types of insects will assist in your fight against aphids whereas others will be anything but helpful. Some ants farm aphids by storing eggs in their nests over winter. They then carry the baby aphids to young plants in spring. The ants then feed on the sticky honeydew and will fight off predatory insects such as hoverflies to protect their food source. Very clever but not very helpful.
So if aphids and ants are the bad guys who are the good guys? Definitely ladybirds, they love to munch on the bad guys. Ladybird larvae can be purchased and delivered to your home – an easier solution than trailing round the countryside searching for ladybirds to place on your plants. Earwigs, parasitic wasps (yes, wasps can be good guys) and hoverflies are also good guys and lacewings will certainly help you with one lacewing larvae being able to eat as many as 100 aphids in just 1 hour.
Encouraging birds to the garden means you not only have the pleasure of watching them but tits and finches will also help to control pests.