Something is eating my magnolia and the leaves appear to be eaten in a lace like manner. I keep scanning the tree to find what is eating the leaves, but I can't see anything, though the leaves are left in a lace like pattern. The tree is in a large pot on the patio.
Pests on Magnolia
Certified GKH Gardening Expert
This could be Leaf Miners, or several other insects that dine on the leaves.
Treat with Neem Oil and I would treat weekly during the growing season to prevent further insect damage.
Here is a few links for you with more information.