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SYMPTOMS 
Circular to angular brown spots begin occurring on the older, lower
leaves in late June and July. The leaves begin to turn bright yellow,
orange or red and fall from the tree. As the summer progresses, many
infected trees will have dropped all but the newest leaves. Repeated
infections year after year will severely stress a tree and reduce its
longevity.
DESCRIPTION
OF PEST
This fungus colonizes leaf tissue and causes distinct sunken brown spots
on leaves. Within the spots, there may be black fruiting structures
evident with magnification.
LIFE
CYCLE
Spores
are produced within tiny stromata which erupt through the leaf surface.
These spores can be splashed from leaf to leaf causing new infections
during warm, wet weather.
MANAGEMENT
| CHEMICAL Fungicides can be utilized to control Cercospora leaf spot on susceptible crapemyrtle varieties. This should be started in early summer when the spots are first noticed and continued at one to two week intervals when the weather is warm and wet. Consult your local Extension office for fungicide recommendations. BIOLOGICAL The best biological control is selecting a planting site with good air circulation so that the foliage will dry quickly. Thinning interior branches will also promote air flow. The varieties Apalachee, Caddo, Catawba, Sioux, Tonto, Tuscarora, Tuskegee, and Yuma have been shown to have resistance to this disease. |
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Small
distinct spots and yellowed leaves may be evident in early summer. |
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A
closer view showing the sunken, |
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By
late summer all but the newest leaves have dropped from this tree. |
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A
magnified view of the lesion shows the small, black fruiting structures (stromata) which contain masses of spores. |
