Elizabeth Bush, Virginia Polytechnic Institute and State University, Bugwood.org
Entomosporium leaf spot is one of the most common diseases of Photinia in the landscape. Other names of this disease include Diplocarpon or Fabrea leaf blight. This pathogen will also infect more than 60 species of landscape plants in the rose family. Susceptible genera include Amelanchier, Aronia, Chaenomeles, Cotoneaster, Crataegus, Cydonia, Malus, Photinia, Pyracantha, Pyrus and Sorbus. Symptoms begin as small spots that usually coalesce into large dead areas. Lesions on plants such as Photinia frequently have reddish brown margins with gray centers. Infected plants will defoliate before mid summer and secondary infections frequently cause extensive disease on new foliage.
Rake and dispose of infected foliage, avoid overhead irrigation, also avoid mid summer pruning that may produce susceptible foliage and select resistant varieties when available. Registered fungicides may be needed on highly susceptible cultivars.