I have a plum tree in my backyard. It is very old and hardly bears any plums but it gives good cover in the summer. It is covered with a silver hairy disease that is very hard to kill or remove. The birds nest in it and they carry the spores on to my concrete tile roof. The roof is covered in this silver cobweb effect spore and is very hard to remove. I cannot jet spray it off, as it will cause leakage in the tiles. Is there a product that will kill this disease? I have had it sprayed by professional sprayers but it still remains.
Certified GKH Gardening Expert
It sounds like it may be a form of lichen. Regular applications of fungicide should clear it up. This article may also help: