Derbyshire, United Kingdom

My Robinia is looking very ill. It came back well after the winter and the leaves were beautiful but the colour seemed to deepen, then it got brown crispy bits on it and the leaves are falling just leaving the leaf stalks behind. I had the same thing about three years ago and I lost that tree. I left it a couple of years before planting another one in a different spot. Any ideas on how to save it? Is is something contagious, in which case should I destroy it quickly as I have another tree as yet healthy.
All suggestions greatly appreciated.

• 30 Jun, 2011