Azalea Disease on Leaves
I have a number of Azalea plants in pots that I've had for about 11 years. I keep them under shade cloth in the summer in an easterly direction and in the winter I put them in a round garden on my front lawn. They love it there and they always flower beautifully. I live in the central wheatbelt of Western Australia and our summers are very hot and winters are cold and frosty. This does not seem to worry them at all, but this year they have what appears to be a white to grey appearance on the outside of the leaf and on the under side little black spotted things. Please can you help, as I said the summer doesn't worry them as long as they are under the shade cloth, and of course, kept watered and the cold frosty mornings when we have them in winter doesn't bother them.
Certified GKH Gardening Expert
The problem could be attributed to the azalea lace bug. Here is an article that you may find helpful: https://www.gardeningknowhow.com/ornamental/shrubs/azalea/azalea-lace-bug.htm