Fungal causal agent: Cercospora lythracearum

Symptoms: Initial symptoms are circular to irregular yellow spots, that turn brown usually in the lower canopy. Leaves can become distorted. Heavy infection leads to severe defoliation. The disease can affect plants in both nursery and landscape.

Management:  Avoid using susceptible varieties of Lagerstroemia indica, and L. indica x fauriei. Diseased cuttings are a major source of the pathogen spread, and hence should be avoided in container-grown plants. In the landscape, infected dead leaves from previous crop can lead to spread of the fungal spores by wind. Manage plant canopy by improving air circulation. A fungicide management plan should under ideal conditions for disease occurrence. The list of resistant varieties can be found in the reference 

Reference: http://www.aces.edu/pubs/docs/A/ANR-1047/ANR-1047.pdf

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