As attractive as they might be, photinias are prone to a fungus leaf spot called Entomosporium. The red tipped photinia is one of several species that is susceptible to the disease.
Like most fungi, entomosporium thrives in cool, moist environment in the fall and spring. During periods of rain, the fungal spores will spread through water and wind, traveling from one leaf to the next until the whole plant is infected.
It causes small circular red spots to appear on both sides of the leaf. Over time, grey spots will develop in the center of the spots. Serious infections will have large blighted areas and the disease can spread to the branches, causing cankered areas. As well, fungus leaf spot can cause premature leaf drop, resulting in large bare areas in the bush. The fungus won’t kill the plant immediately, but it will return year after year until the plant dies.
That being said, depending on the severity of the situation, photinia leaf spot can be manageable. With any disease, prevention is the best cure. Plant photinia in full sun and provide good circulation. Give it enough space to breathe. Photinia hedges are more susceptible to the disease than single plants. It is a good idea to thin out hedges that are too close together or too dense to prevent the growth of fungal spores.
If the plant does get infected, immediately rake up fallen leaves. Next, remove all the diseased branches and leaves; cut heavily damaged plants all the way back to increase air circulation. Be sure to prune the the lower branches from the photinia, including healthy ones, as this will protect the lower areas from infection. Cover the area under and around the shrub with mulch to cover any leaf parts and photinia fungus spores that remain.
It’s best to do the pruning on a dry, winter day, as photinias go dormant during those months and won’t produce any new spores. In addition to pruning, do not over water; water photinias only when necessary.
Another option is to use the appropriate fungicide to get rid of the disease. Treatment should begin early for the best results. In the spring and wet periods in the fall, apply the fungicide every 10 days or so. It is not necessary to spray during hot, dry periods.
If these solutions aren’t enough to save the plant, you could always remove the diseased photinias and replace them with something else. Consider planting a mix of bushes, as they are more resistant to leaf spot disease.
- Red Tip Photinia (funflowerfacts.com)