What is that white powder on your ninebark?

I have a center glow ninebark and have noticed that some of the leaves have a very fine white powder like substance on them. It’s not on the entire plant but just one section. Any suggestions. Thanks in advance

The problem sounds like powdery mildew, a fungal leaf disease that looks like “powdery” white or grey blotches. Although powdery mildew is unappealing to the eye it is rarely fatal. However stress on the plant can occur and make it more susceptible to other infections that weaken the plant. If the fungus spreads to cover the majority of the leaf’s surface, photosynthesis cannot be performed properly and the leaves may begin to fall prematurely. The fungal spores overwinter in plant debris and begin producing new spores in the spring. These spores are carried to plants by wind, insects and splashing water. Powdery mildew can spread from plant to plant. The fungus needs ample conditions to thrive including: Dampness or high humidity, crowded plantings, and/or poor air circulation. Once plants have become infected remove and destroy all infected plant parts. Improve air circulation by thinning or pruning. Don’t fertilize until the problem is corrected, this fungus prefers young, new growth. Water plants from below not from above. You may also choose to use a fungicide containing potassium bicarbonate, sulfur or copper. Always read the label and follow instructions accordingly. Applications of fungicides may need to be re-applied every one to two weeks to provide future protection.