greenfly on herbs

[shivvy]

I have discovered what looks like greenfly on the stems of my parsley plant. Is there anything I can do to get rid of them and still be able to eat the parsley?
Also, if I should chuck it out and buy more, what can I do to stop them invading again? (I have 2 other plants in the kitchen but neither of them seem to be affected)

[BBWCHATT]

http://www.gardenaction.co.uk/techniques/pests /aphids.htm

It is unlikely to kill the plant, but it can seriously weaken it.

Other friendly ways of controlling aphids include rubbing them off with your fingers, spray them off with water and the use of insecticidal soap (a potassium-salt soap available at most garden centres). Many people have success by spraying weekly with very diluted washing up liquid - about one teaspoon of Fairy Liquid to a couple of litres of water.