Photinia leaf spot disease is caused by a fungal pathogen. This disease commonly occurs on the southern landscape plant, red tip photinia. it also defoliates Indian hawthorn, loquat, flowering and fruiting pear, hawthorn and firethorn.
Infections start as small, black spots on tree leaves. The border of these sports may be reddish. After the tissue dies, small black fruiting bodies develop in the center of the spots. As a result of this season-long disease, photinia hedges can become thin and scraggly due to premature leaf drop of infected leaves.
To minimize the effects of this disease, start applications of fungicide at bud break and repeat until the majority of leaves have matured. This may require at least three applications in the spring and three applications from mid-October to late November, when the cooler temperatures and rainfall lead to more fungal activity. Additional applications may be required if disease-favoring weather goes on for a long time.
Another tip is to avoid planting photinia in shaded locations as the disease will be more severe. Red tip photinia is a high maintenance species due to the rigorous fungicide program that is needed to keep the leaves on the plant.