Neem will not get rid of it. Just help prevent it. If u have Powder mildew in veg. that shit spreads like wild fire, and u might think it's gone...Then wham hits in week six of flowering your screwed...I know! I never used serenade, but my friends has, it helped some & not others. And he had huge crop ended up using eagle 20 in week 2 of 12/12 never saw it again. But that shit it a powerful fungicide. People shy away from it, cause it's not organic. Just some input. Hope you can kill the shit! Good luck & Peace.