Our Liriodendron seems to be badly infected. Lots of leaves with black spots. Lots of leaves yellowing and dropping. Found paper on Internet re infection by 2 species of fungus tat cause the symptoms our tree is showing. It had similar problem last year, but it is worse this year.
Are there fungicides available in Ontario to treat our tree?
Liriodendron trees are lovely trees and usually worry free but there are a couple of problems that can affect them. Judging from your description it could be one of two things. A fungal leaf spot could be the issue, which affects the tree causing the dark spots and then the leaves to yellow and fall. This issue is usually not terribly serious if you practice good tree maintenance by raking up all of the affected leaves and disposing of them in the garbage keeping the disease from further infecting the trees. Once the tree is heavily affected I am afraid that chemical control may not be possible. Another potential cause is hot dry weather, which also causes yellowing and leaf drop preceded by small angular brown spots on the leaves.
Without seeing the tree it is hard to identify the exact problem or the right solution. It might be best to employ a good arborist, who could identify the issue and treat the tree effectively.
Here is a fact sheet on the Liriodendron and a link to Landscape Ontario with a list for certified arborists:
I wish your Tulip Tree a long and healthy life.