Dogwood is infected
Hi Experts, I have an old, mature dogwood (the trunk is nearly 1' in diameter) that suddenly looks very sick this year. It bloomed back in May, but now, looking at the leaves, then entire tree looks badly infected. Can you identify what's going on, and, is there anything I should do about it? Thanks a lot. Pictures attached. Dave Silver Spring
Montgomery County Maryland
We looked at the photos. Dogwoods in general are susceptible to several fungal diseases such as spot anthracnose and powdery mildew. Your photos of the foliage show spot anthracnose. Most likely powdery mildew will show up too. These diseases have been common due to our cool wet spring and we have been receiving many questions on these diseases.
Spot anthracnose (leaf spot) is not usually a big problem, but we're seeing a lot of it this year because weather conditions were perfect for it. Since disease severity is sporadic depending on how wet the spring season is routine fungicide applications are not recommended. https://extension.umd.edu/hgic/topics/spot-anthracnose-dogwood-or-elsino%C3%AB-leaf-spot
There is a range of susceptibility among dogwood to powdery mildew. The best recommendation is to plant powdery mildew resistant varieties in the future. Pruning for air circulation may help. You will have to monitor the plant in the future and decide if you want to spray fungicides or horticultural oil products listed for powdery mildew. This disease does not kill the plant but can weaken it.
At this point, make sure mulch is no thicker than several inches and keep it away from the base of the trunk. Water the tree during dry periods. Prune any dead wood.
Here is more on care and management of disease of dogwood. Look for resistant varieties in the future.