Excuse the pun but for most gardeners, in the summer months, one of the biggest bugbears is aphids like greenfly and blackfly and related insects on flowers, fruit and vegetable crops.
What Are Aphids?
Aphids are common sap-sucking insects that can cause a lack of plant vigour, distorted growth and often excrete a sticky substance called honeydew on foliage which allows the growth of sooty moulds. These tiny insects pierce the stems of plants preferring tender new growth to established greenery sucking out the nutrient-rich sap depriving the plant of the fuel that it needs to thrive.
Aphids can be quite secretive. Look for them on new growth, in leaf crevices, clustered on buds, along stems or under leaves. The tiny insects are usually found in groups and you may find some with wings which is a sign that the colony is about to disperse onto new host plants. Woolly aphids are easier to spot; they shield themselves in a mass of white, woolly wax on tree branches
While aphids in general feed on a wide variety of plants, different species of aphids can be specific to certain plants. For example, some species include bean aphids, cabbage aphids, potato aphids, green peach aphids, melon aphids, and woolly apple aphids.
Some aphids transmit plant viruses which can be a problem on strawberries, raspberries, tomatoes, cucumbers, dahlias, tulips, sweet peas and many other plants.
While an aphid infestation may start out slowly, aphids reproduce quickly and a colony of these pests can easily destroy entire crops if left untreated.
For minor infestations of aphids, it may be possible to physically remove the insects from your plants by brushing or pinching the pests from stems and leaves or if the infestation is contained to one or two stalks or branches, prune off the affected branches and drop them into a bucket of soapy water to kill the aphids.
It is possible to spray aphids off plants with a garden hose. While this method may harm younger, more fragile host plants, it can be quite effective at controlling small aphid populations on more robust and well-established plant.
Some people use soap and water sprayed on the plant but this can kill beneficial insects like ladybirds, lacewings and hoverflies.
Another option is to attract aphid predators to your gardens such as Ladybirds, lacewings and Hoverfly larvae by planting plants that they like such as marigolds, calendula, alyssum and Echinacea. Some herbs including dill, fennel, parsley, thyme and mint also attract these predators so it’s a good idea to plant them in your veg plot.
Aphids are part and parcel of gardening but they can be controlled with the right actions.