Crapemyrtle – Black Leaves

Q: I have eight large crepe myrtles that have a black fungus and tiny insects on nearly all of the leaves.

A: You have a beautiful example of crapemyrtle aphids. The white things on the leaves are their cast scans.

The black coating on the leaves is sooty mold that grows on the sticky honeydew the aphids excrete. You may see the black coating not only on the leaves but also on the trunk and on mulch underneath your plant.

Rain will eventually wash it away once the aphids are gone.

Use imidacloprid (click for sources) systemic insecticide according to label directions. You may be able to get two years of control with only one application.