Jason,
As much as I have read, as many people as I have listened to, as many different things I have tried, I have not found (in my experience) s specific chemical I would actually recommend. Most all of the treatments have worked to some degree, but nothing I have used has worked as good as I would like. I will say tops on my list to try is Azoxy 2SC Select Fungicide, active Ingredient: Azoxystrobin 22.9%.
The reason I have not tried a lot of the more effective (according to what I read) products has been the expense. Azoxy 2SC Select Fungicide is $124.99 a pint, the cheapest I have found it (if anyone has found it cheaper please let us know). Now this amount even in a pint size is more than I would use personally in years, and that is the problem. I feel after just a couple of years the product would began to lose it's strength. If it would stay effective for five or more years it would be worth it to me.
I have had decent results from the "contact" products, but not so much success with the systemic products. I say that because I had to spray more on a 7 to 10 day spray schedule with them, when I wanted to be more on a 15 day or more spray schedule.