United Kingdom 
A customer of mine, is concerned about some kind of mold or fungus which is growing on the main trunk of his apple tree.
I've taken a couple of pics to help diagnosis, but can anyone confirm what the problem is and any suggestions on a cure
27 Nov, 2012
Answers
it is dark but as mg sais it looks like harmless lichen . my acer trees are coverd in it but fine .
28 Nov, 2012
If you are refering to the white/grey scabby stuff then that is lichen, an indicator of good air quality and not harmfull to the trees.
28 Nov, 2012
thanx bulba
29 Nov, 2012
The images are so dark it is not possible to give a definite answer but it 'could' be lichen. Could you take better photos please.
28 Nov, 2012