Sick? Magnolia tree - Ask Extension
I live in Corvallis (southtown) and have a mature magnolia tree in my yard. I just recently noticed a few of the leaves seem to have a blight on them....
Knowledgebase
Sick? Magnolia tree #809426
Asked September 04, 2022, 4:05 PM EDT
I live in Corvallis (southtown) and have a mature magnolia tree in my yard. I just recently noticed a few of the leaves seem to have a blight on them. Turning brown and with a fuzzy white growth on the damaged section. What might this be and how do I treat it? The tree seemed healthy until just recently.
Benton County Oregon
Expert Response
The images show me one leaf that is necrotic (dead, brown) from the tip to half back on the leaf. The necrotic area appears to have has mycelial growth of a fungus. There may be two different things to explain the issue but without more detail about the rest of the tree these are only guesses.
First, these may be older leaves that are in the shade and are being shed by the tree. Secondary fungi have colonized the dead areas and would not be a concern. These could be sun burned leaves on the outside of the tree that also have secondary fungal growth.
There is a lower chance that this is powdery mildew which can be common this time of year. The symptoms are not quite right. You can read more about this disease here:
https://pnwhandbooks.org/plantdisease/host-disease/magnolia-powdery-mildew
First, these may be older leaves that are in the shade and are being shed by the tree. Secondary fungi have colonized the dead areas and would not be a concern. These could be sun burned leaves on the outside of the tree that also have secondary fungal growth.
There is a lower chance that this is powdery mildew which can be common this time of year. The symptoms are not quite right. You can read more about this disease here:
https://pnwhandbooks.org/plantdisease/host-disease/magnolia-powdery-mildew
