Hello, I planted a 7-gallon dogwood (cornus florida) in late March of this year. Everything was going well until the past few weeks, when some of the leaves have been either wilting or having blotches of yellow then dropping off. There also appears to potentially be a thin amount of whitish powder on the surface of the leaves. The tree is in a shady location and I have been watering it about once per week, if it doesn't rain. I live in University Park, MD, and there are many other dogwoods in the neighborhood with no such problems. Also, I planted some other 7 gallon trees (amelanchier canadensis and nyssa sylvatica) at the same time, from the same nursery, and they are all doing well. Do you have any idea what could be the problem? PS- I can confirm that there has been no cicada damage (I have seen what it looks like on other trees and this is different).