There are many species of aphids but almost all respond to the same control and treatments. A large variety of chemical sprays are available from your garden centre to treat aphids, but all will have some bad effects on other beneficial insects and wildlife.
Where edible crops are sprayed with these chemicals, some of the chemical will also remain within the flesh of the plant.
A better line of attack is to encourage other insects which feed on aphids. Research has very positively shown that planting certain plants (e.g. tagetes, calendula, poached egg plant, morning glory) near the plants which are often attacked by aphids results in much lower numbers. The aphid’s enemies include hoverflies, ladybirds, lacewings and birds.
The important point to consider with attracting beneficial insects is that those insects rely on a steady source of aphids. When the aphid population drops below a certain level, the insects will go elsewhere. This in turn will allow the aphids to multiply. The solution to this problem is the humble nettle
There are a couple of reasons why nettles are so good for protecting your plants. Firstly, they will attract the nettle aphid which is a good source of food for lots of aphid eating insects. Nettle aphids are also one of the earliest to appear in the year which is good news for the ladybird. Nettle aphids won’t attack your other plants because they only feed on nettles. So, not all aphids are bad news!