Anthony from Aptos writes
Black fungus on limbs and trunks
Monterey Garden Phos Systemic Fungicide can be used to treat and prevent sudden oak death and many other oak diseases. Here is actually a release from July about this disease being found in Illinois.Typically trees that are infected are not able to be cured but must be diagnosed and removed very carefully so as not to spread the disease. Here is another article about this disease.
Answer last updated on: 02/15/2021