Q.Rust Disease on Grass (Lawn)
I think I might have rust on my grass. What is it? How do you get rid of it?

I suggest you contact your local extension office (found under gov't in your phone book) since rust is usually caused by a fungus, they will be able to help you find out exactly what you have and be able suggest the best options to control the problem. This article will give some background info:
https://www.gardeningknowhow.com/ornamental/flowers/roses/yellow-rose-leaves.htm