By Alanbarwick
Clwyd,
United Kingdom 
Hi, My acer brilliantissum has developed curled leaves and little red blisters on the leaves.I have sprayed with a combined fungus /bug buster but does any one know what this is. There is a fantastic specimen up the road that has the same problem. This is the second year this has occurred
17 Jun, 2013
Answers
Thanks, Ive stripped the worst off, do you know if
its terminal?
18 Jun, 2013
It's specific to sycamores (which A. pseudoplatanus 'Brilliantissimum' is) and is the living quarters of a gall mite, aceria macrorhynchus. I only know this because it used to fascinate me as a child. Difficult to anticipate, and deal with, and once the mite has done its work no spray will take off the tiny red castles. I suppose a clip over so any new growth will be clean is one course of action
17 Jun, 2013