By Joolz
Cornwall,
United Kingdom 
hi there,im new to looking after apple trees and mine is covered in a white dusty fungus that turns to a rusty coloured sticky substance when you touch it, what is it??? and how can i get rid of it...pref organicly? joolz.
10 Aug, 2011
Could be mildew, could be scale, could be woolly aphid - need a photograph really.
10 Aug, 2011