Entomosporium Leaf SpotCausal Agent: Entomosporium maculatum
Hosts: Red tip photinia species.
Symptoms: Tiny circular, red spots on both the upper and lower surfaces of young expanding leaves. Leaf spots on the mature leaves have black to gray centers with a distinctive deep red to maroon margin.
On heavily diseased leaves, the spots merge, forming large, irregular blotches. Tiny black specks, fruiting bodies of the fungus, are often found in the center of each leaf spot. Light infections usually cause little more than cosmetic damage, while severe infections often result in early and heavy leaf drop. Severe defoliation not only slows growth but also increases plant sensitivity to environmental and cultural stresses.
Masses of spores are released from the diseased areas from late winter through much of the growing season. These spores are spread to healthy foliage by a combination of splashing water and wind. The wetter the spring, the more severe the spotting and shedding of leaves.
Control: Purchase plants showing no symptoms of Entomosporium leaf spot. Do not locate new plantings near established diseased plants. If possible, collect and discard fallen diseased leaves, an important source of fungal spores. Currently, no selections of red tip photinia are resistant to Entomosporium leaf spot but fungicides can provide effective protection. Apply fungicides from the bud break until all new foliage has matured. Please contact your local county extension office for current information.
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