Asked by Anh (bananhie)
Editor: Ahn, we've written a few posts about how ladybugs are an aphid's worst enemy (Ladybugs and Your Garden and Pest Control: Ladybugs 101). Also, water, vinegar and dish soap are said to also be effective deterrents. You can also do some companion planting of 'sacrificial plants,' like nasturitiums or marigolds to attract aphids away from your vegetables. A reader in this comment thread swears by insecticidal soap to get rid of the aphids on her tomato plants.
Readers, other suggestions?
(Image: Flickr member Accretion Disc licensed for use under Creative Commons)