If you have a JDL store nearby, go buy some Armada and a hose end sprayer. It will take you 30 minutes the first time you do it because you will be bitching at me for telling you to do it. Then, about 30 days later it will take you about 10 minutes to spray it. If you do this a couple of times a year, you will basically eliminate lawn diseases.
Alternate option, go by something at home depot for lawn diseases. It probably won't work as well, but you can do this pretty easily.
If you do the JDL option, let me know and I will PM you some details.