Question
flowers on tree keep dying each year.srayed with mancozeb weekly. doesnt seem to work.noticed a lot of black spots on tree branches.could you please help

Answer
Hi

Could you check the spots on the trunk with your fingernail and see if they will scrape off and have liquid inside when squashed.  A close-up picture would also help.  If this is the case, it is scale insects which can cause the symptoms you describe.  Please respond back with your observations and I can make a better recommendation for control.  Thanks.