Brown Spots Probably Disease Problem on Tree Photinia

Q. Can you tell what the problem is with my patio tree and what I can do about it? The leaves are all covered in brown spots. I am not sure which plant it is.

A. From the looks of the plant it seems to me to be a photinia pruned as a patio tree. From the pictures you sent with the black spots on the leaves I think it is either photinia leaf spot disease or more likely, anthracnose. Neither one do we see much here.

            Both diseases can attack photinia and Majestic Beauty hawthorne so if your tree is either one of these, this might be the problem. Majestic Beauty is particularly prone to anthracnose while the smaller shrub-type hawthornes usually are not.

            Unhealthy plants are MORE likely to get a disease than healthy ones.  Anthracnose usually makes dark brown or tan spots that look like irregular targets with concentric irregular rings in them.

            Poor air circulation and wet leaves will make this disease worse. These diseases are thought to spread when leaves are wet or if you spray them with a hose to keep them moist. So irrigate only at the base of the tree and do not spray the leaves.

            The tree and the interior of its canopy need air circulation to stay dry. Prune out entire limbs from the trunk or branches so that air can move through the canopy and not stagnate.

            Leaf spot disease is caused by a different fungus and can re-attack the tree year after year if you don’t pick up diseased leaves that have dropped and dispose of them.

            The disease is less likely to be active when it is hot out. So if you have to spray the foliage then avoid doing it during the cooler months. Do it during the summer in the morning hours.

            I noticed something on the bottom of your leaves when I magnified the picture you sent. Aphids? Soap and water sprays on the undersides of the leaves will control them. Do it every three days for about four applications.

            Your tree is not in the best of health. Apply iron chelate in the form of EDDHA and a good flowering tree fertilizer now, in very early spring, and once again later in the season.