Aphids or most commonly known as greenfly or blackfly are very common, soft-bodied sap sucking insects. They feed on a wide variety of plants, houseplants, trees, fruits, vegetables and greenhouse crops are all affected. There are more than 500 different aphid species in the UK, some of them are very plant specific and feed only on a handful of plants but many of them damage lots of different plants. They colonise on the new growth of the plants, around buds, flowers and the underside of the leaves. You can find greenfly on roses and on houseplants, blackfly on broad bean and on artichokes. The many species vary in colour from yellow to green, brown to black.
As they suck the sap out of the plants the plant will get weaker, producing less crop or in cases completely blocking flowering and growing. The leaves curl and the new growth will wilt eventually.
Aphids can transmit plant viruses and other pathogens too wich will further weaken the plants and you end up with less or no crop.
It is important to control their number, I say control because it is near impossible to get rid of them completely.
beneficial insects can do a good job of controlling them but in warm weather the aphids can produce a new generation within 4 days so it is really necessary to act fast as the beneficial insects will not cope with such a vast amount of aphids. Ladybirds and ladybird larvae, hoverfly larvae and lacewings larvae are all good predators and will eat lots of aphids.
Most aphids excrete sweet honeydew and in some cases ants feed on it and protect the aphids from the predators. This photo of my artichokes on my allotment showing the yellow meadow ants farming the aphids. The ants even keep the aphid eggs during the winter in their nests underground.
So to get rid of the aphids completely is not an easy task, but you can control their number. A simple washing up liquid and water mix directly sprayed on them will kill them as they breathe through their skin and the soap will stick to their skin stopping them breathing. Also to repel them you can use garlic spray, the best is if you have infected plants to mix a little washing up liquid in your garlic spray for killing and repelling them at the same time.
