Answer: Unfortunately, based on your description it is difficult to make a definite diagnosis. Azaleas may yellow and defoliate for a number of reasons ranging from fungal infection to poor drainage to overly alkaline soil to an insect problem. Rather than treating without knowing the specific cause of the problem, I would suggest you consult with your county extension for a specific diagnosis and then work from there. In most cases it is not recommended to feed plants that are stressed, however if the problem is related to the soil pH there is a possibility that some type of soil amendment is in order. The only way to know that for sure would be to run some basic soil tests and see. Your county extension should also be able to help you with the tests and interpreting the results. In the meantime, although it is tedious, it is a good idea to clean up, remove and destroy fallen leaves and dead twigs so that there is less chance of reinfection if it is an insect or a disease problem. I'm sorry I can't be more helpful.
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