It probably will not kill them. Espoma fertilizers are generally slow acting. Adding additional fertilizer by using the Bayer product may or may not cause some problems with overly lush growth that will not harden off before winter. If you really feel you must use a fungicide - it's often not necessary - why not use a spray rather than the systemic drench which includes fertilizer?

Actually fertilizing a stressed plant is not a good idea. Plants are more vulnerable to pests after they are fertilized. Hence, the Bayer product sounds like a bad idea. The Espoma HollyTone is an excellent product. Fungus on an azalea can be caused by drought, so a pesticide is not always the solution. Let us know the nature of the fungus and we can find a better course of attack.