Azalea – Black Dust on Leaves
I have an azalea in my garden which has flourished year by year. I have notived the leaves are covered in a black powder, some denser than others, some not affected. It has become hard and difficult to wash off. I have sprayed the leaves both sides with a general pesticide for plants and bushes. Apart from the deposits, some of the flower petals now appear to have just one black spot. What is wrong and how can I clear the problem?
Certified GKH Gardening Expert
It is most likely either sooty mold or sooty canker. Here is more information on these diseases: https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-disease-identification-sooty-canker-fungus.htm, https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm Sooty mold normally indicates a pest issue. You should check the plants for pests as well.