The grow room is all new, with no preexisting plants. The clones that were brought in have this powdery dusty stuff on the leaves, I took some pics so you can see. Is this powdery mildew? From what I've been reading it's impossible to kill completely, is that correct? If it's not powdery mildew what do you think it is? They are supposedly pre 2000 dj short blueberry clones, not that it matters much. Thanks in advance for the help.