Beautiful yellow spots on apple tree leaves
What is this and how do you treat it? It appeared in the last month, it is only appearing on our apple trees. We planted them in March they have been doing well until this weekend when I went to water them I noticed the leaves the last two weeks I have sent the kids to water them. They are Macoun, Baldwin and golden and delicious and planted this spring
Frederick County Maryland
This looks like a rust disease, cedar apple rust. Cedar apple rust disease alternates between apple and cedars. This fungal disease will also be worse in some years that have very wet weather at crucial times in spring.
In general, apple trees are very susceptible to insect and disease issues and eventually require a spray schedule for control. We recommend people with tree fruit learn about the major insect pests and diseases and management options.
You can spray the apple for rust but not the cedars. See cedar apple rust on ornamentals. http://extension.umd.edu/hgic/rust-diseases-trees-and-shrubs
See cedar apple rust on apples and a spray schedule from VA Tech.
It is too late to spray this year. You will have to begin next spring. The best recommendation is to plant resistant varieties of apples. Rake up and discard any foliage from the ground and discard in the trash.