Q.rusty, dead leaves on azaleas
One of my azaleas, about 5 years old, has rusty, dead, leaves. It is in direct sunlight (just like the other one that is fine). I also have a forsythia with the same problem. We have many other shrubs that are suffering from the heat, but are doing OK. We live in the country and have dogs roaming freely. Could dog urine cause this? What can we do to save our shrubs? We work hard to keep our 3 acre yard looking good. We really don’t want to lose these plants. Thanks for your help in advance.

It sounds like your plant is infected with Rust fungus.
Here is more information for you.
https://www.gardeningknowhow.com/ornamental/shrubs/azalea/no-leaves-on-azalea.htm