My neighbour has three cherry trees of different varieties in her garden. All are affected by the same problem. A fruiting cherry and a Japanese flowering cherry in the front garden have been largely defoliated (the picture above is of leaves taken from the flowering tree yesterday). The problem has now spread to the gean in her back garden. I have two amelanchiers in my front garden which seem OK. The large holes look like slug damage, but the smaller pin holes are strange to me. Can someone please suggest the culprit(s) and potential treatment(s)?