Pembrokeshire, United Kingdom

My young (12 foot) damson tree is suffering from tiny insects, possibly aphids on the underside of all its leaves and is looking very sorry for itself. The insects appear to be black and there also seems to be a fine white webbing all over the underside of every leaf. This has happened every year so far (ie three years in succession). I have about 10 damsons on it this year so am reluctant to use insecticide. any ideas please?

• 21 Jul, 2011