Our 15 year old Texas ash has less leaf production this year. It also has a small amount of algae on the trunk, and some of the branches have small white spots on it. Also, a few of the branches closest to the trunk have died.
Any suggestion would be appreciated.
Fusicoccum Canker could cause branches to die and might be responsible for the white spots on the branches.
There are several foliar diseases of ashes that might have caused leaf loss, anthracnose being only the most common. It, however, has many symptoms that don't seem to match yours, based on your description.
This list of ash pests with diagnostic descriptions can help you match your symptoms with known ash diseases and get ideas about how to control them, and this discussion of White Ash contains an informative section toward the end about common diseases of that tree. Texas Ash (Fraxinus texana) is so closely related to White Ash (Fraxinus americana) that many taxonomists consider it to be just a variant of White Ash, so any information you find about White Ash will probably apply to your Texas Ash.
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