I have received this call a lot this spring. “What are those spots on my Indain Hawthorn?”  Well, it is most likely Entomsporium Leaf Spot. This fungal leaf spot disease affects woody ornamentals in the rose family including indian hawthorne, and the red tip photinia,. Entomosporium leaf spot became so severe on red tips that the plant is no longer recommended to be used in the landscape.

Symptoms of Entomsporium include distinct circular red lesions with gray centers forming as the lesions expand. Dark specks (fruiting bodies of the fungus) may be visible within the gray centers. Spots may also develop on the petioles and new shoots. Badly infected leaves often fall and plants may look thin. Repeated loss of the leaves results in weak plants and dieback of branches.

Well, then what do we do about my hawthorn?  The first thing to consider is to plant varieties of Indian Hawthorne that are not susceptible to Entomosporium leaf spot. Good plant selection will give ‘permanent’ control of this disease. Resistant varieties include Olivia, Eleanor Tabor, Indian Princess, Gulf Green, Georgia Petite and Georgia Charm. Susceptible varieties include Bay Breeze, Cameo, Springtime, Pinkie, Enchantress, Heather, Snow White, Clara, Ballerina, Bay Breeze, Cameo, Elizabeth and Kathy.

The disease is favored by moisture on the leaves. Homeowners should avoid wetting the foliage when watering and maybe use drip irrigation. Schedule the irrigation timers to water from 10 pm to 10 am and irrigate deeply and infrequently. If you are planting your hawthorne, then they need to be in full sun and plant farther them apart so plant leaves dry more quickly. Selective pruning to reduce the number of branches can increase air circulation through the plant and reduce disease incidence. Sanitation is very important as infected leaves serve as a survival site for the fungus between infection periods. This disease can be spread by rain or overhead irrigation because the water splashes the fungal spores from infected to healthy leaves. Remove severely infected leaves on the plant and fallen leaves from the area and throw them away. The fungus prefers to infect tender, young leaves. Practices that encourage new growth during the growing season, such as pruning and fertilization, should be avoided. Infection occurs primarily in the milder weather of  the spring and the fall, especially during periods of rain. During this time, fungicides can be used  preventatively on plants with a history of severe infections. If you have any comments or questions about Entomosporium leaf spot then call your local Extension agent.