Evergreen Magnolia Trees
We have a mature evergreen magnolia tree that appears to be losing more than the usual amount of leaves at this time of year. In addition the new leaves are a much lighter green with brown spots. In prior years the new leaves have been dark green. This year the tree does not look healthy.
Benton County Oregon magnolia
Can you provide some photos so we can have our expert look and see if they can spot the issue. Up close of the leaves and a further away shot to show the whole plant.
Here are a few photos. It is hard to really see the entire tree and how unhealthy it looks compared to prior years.
Thanks for sending the pictures. In these springs of cool weather and lots of moisture, a variety of fungi proliferate in the Pacific Northwest, and your plant looks as if it has a fungus identified as Phyllosticta leaf spot. Here's a link to an article about the fungus and its control. You can start removing and destroying fallen leaves whenever they drop, so there will be no fungal spores that overwinter on the ground.
If you feel you want to attempt to control with chemicals, only the Bonide Fungi-Onil is available to homeowners, and you should follow the directions on the label for effectiveness and safety.
Hope this is helpful. Good luck!