Our well established Wisteria's older branches have developed grey dust like spotty fungus - no leaves, flower heads have formed but have dried out. On younger branches both leaf and flowers are looking very healthy. No signs of gall.
Certified GKH Gardening Expert
It sounds like you may have powdery mildew. This article will help you: https://www.gardeningknowhow.com/plant-problems/disease/get-the-cure-for-powdery-mildew.htm