Q.White Powdery Bloom
I have noticed a white powdery bloom on this shrub. It’s currently full of small bees during the day, they seem to like the tiny green flowers. I have pruned most of the affected shoots and burned them.

Certified GKH Gardening Expert
It looks like powdery mildew. It is important to pick up any leaf litter and discard to help prevent it returning next year. Here is more:
https://www.gardeningknowhow.com/plant-problems/disease/powdery-mildew-homemade-and-organic-remedies.htm
https://hgic.clemson.edu/factsheet/powdery-mildew/