|I have ten Diablo Ninebarks that were purchased a couple of years ago at the Hinsdale Nurseries in Willowbrook Il. They are all coming down with what appears to be a powdery mildew, and the leaves are crumpling. Some of the branches are dying and had to be eradicated. I am reading alot of articles about other people that have the same problem. I started spraying them once a week with ORTHONEX, and now I am using Ortho RosePride Rose and Shrub Disease Control with the active ingredient being 6.5% Triforine.|
|Triforine is a locally systemic fungicide used for black spot, powdery mildew, and rust of roses, powdery mildew on azalea, begonias, delphinum, kalanchoe, plane tree, calendula, crepe myrtle, dahlia, euonymous, Jerusalem thorn, lilac, phlox, snapdragons, Photinias, and zinnias, rusts on aster, carnation and oxalis, petal blight on azaleas and rhododendron and Entomosporium leaf spot on Photinia. It sounds to me as though you're doing all you can to control powdery mildew on your Ninebarks. Pruning out the most affected branches will open the plants up to better air circulation which should also help. Best wishes with your ninebarks!