we are in Abbotsford.our cherry trees are forming a white almost powder. It starts on the trunk, unless it is a top graft then the white is starting on the graft. Can be top or bottom or middle of the tree where it starts. It seems to start as spots then become covered. Some of the trees are completely covered but the leaves are fine. So far. We can see nothing on the tree or leaf. We have noticed that the trees in the shade have no white on them as of yet. We have contacted agriculture here in Abby but will not hear from them for a week or two. My neighbour about a mile away has the same problem. I have added some pics to help.