Tree Dying in Summer
Hello. I recently moved to New Market. I’m not sure what type of tree we have. Beautiful dark pink flowers bloomed from it in Spring, but for the past month or so many of the leaves are either yellow, brown, with holes, or have fallen off. I also noticed lots of white splotches on all of the branches. None of the other trees in the neighborhood seem to be like this. There are several caterpillar webs, but I have been told they are probably not the culprit? Any insight or advice would be appreciated.
We cannot say for sure but the tree looks like it may be a crabapple. These trees are subject to several disease problems like scab, rust, leaf spot and powdery mildew.
We cannot say for sure which disease but it is likely scab. The disease is favored by cool, wet springs and overwinters on fallen leaves. If weather conditions are favorable you may see this every year. Rake up and discard all infected and fallen leaves and fruits. Prune trees to promote good air circulation. It is late in the season and no chemical controls are recommended. The best recommendation is to plant resistant varieties. Here is some information from Penn State https://extension.psu.edu/theres-a-flowering-crabapple-for-that
The webbing looks like fall webworm and did not cause the defoliation. If you can reach you can prune out the webbed tents or open up the tents for the birds to eat.