Disease on Crepe myrtles
There are white spots on the underside of the trunks of my crepe myrtles. What kind of disease is this and what should I do about it?
Certified GKH Gardening Expert
It sounds like the tree has scale. This article will help:
I would recommend neem oil. It is both a pesticide and a fungicide, so it will kill the scale and any fungal issues at the same time. It is also organic ans safe to use. Here is more information on it: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
If the spots are more greenish or grayish white and flaky, it is lichen. It is harmless to the tree. This article will explain more: https://www.gardeningknowhow.com/ornamental/fungus-lichen/treatment-tree-lichen.htm