Crape myrtle black spots on leaves - Ask Extension
Hello. Attached are two photos of leaves on my crape myrtle. I recently noticed lots of sooty looking spots on both sides of the leaves. Not all leave...
Knowledgebase
Crape myrtle black spots on leaves #845354
Asked August 12, 2023, 10:45 AM EDT
Hello. Attached are two photos of leaves on my crape myrtle. I recently noticed lots of sooty looking spots on both sides of the leaves. Not all leaves are affected. Can you identify what this is? Does it need to be treated? If so, can you suggest a treatment?
Thank you!
Anne Arundel County Maryland
Expert Response
The black film is called Sooty Mold.
It looks like a relatively minor amount and we wouldn't be too concerned.
Sooty mold is a sign that there are sucking insects affecting the crape myrtle or another overhanging plant/tree. That could include aphids, scale insects, etc. The insects suck sap and then excrete and drop a sticky substance called 'honeydew'. The film/mold then grows on that. Most often we see a film totally covering the leaf, so maybe you don't have a great deal of honeydew occurring.
You don't need to treat for the sooty mold, but there are a couple of issues that are problematic on Crapemyrtles that you can keep an eye out for, such as a new scale insect:
https://extension.umd.edu/resource/crapemyrtle-bark-scale-new-problem-home-landscapes
, crapemyrtle aphids (there is a link about them within the page above), and powdery mildew:
https://extension.umd.edu/resource/powdery-mildew-disease-trees-and-shrubs
Christine
It looks like a relatively minor amount and we wouldn't be too concerned.
Sooty mold is a sign that there are sucking insects affecting the crape myrtle or another overhanging plant/tree. That could include aphids, scale insects, etc. The insects suck sap and then excrete and drop a sticky substance called 'honeydew'. The film/mold then grows on that. Most often we see a film totally covering the leaf, so maybe you don't have a great deal of honeydew occurring.
You don't need to treat for the sooty mold, but there are a couple of issues that are problematic on Crapemyrtles that you can keep an eye out for, such as a new scale insect:
https://extension.umd.edu/resource/crapemyrtle-bark-scale-new-problem-home-landscapes
, crapemyrtle aphids (there is a link about them within the page above), and powdery mildew:
https://extension.umd.edu/resource/powdery-mildew-disease-trees-and-shrubs
Christine
