Transitioning a lawn off chemicals - the summers are wicked wet here

I have a front yard that must be kept monoculture for the HOA.  My backyard, however, I am attempting lots of crazy stuff since it is fenced but that is another story.  I replaced my front yard 1 year ago with Empire zoysia grass.  Before finding permaculture and the like, I regularly applied 4 types of chemicals:  fertilizers, weed n feeds, pesticides, and fungicides.  Since I have switched to zoysia, I have eliminated the fertilizer with composted cow manure and it looks much better (the grass and the soil).  I also use a mulching lawn mower to add the clippings back to the soil and I mow high.  I don't need to use pesticides because all the other lawns surrounding me are St. Augustine so I am a lone grass (although it is a monoculture) in a sea of monoculture of a different grass.  No nasty bugs so far.  I pull the weeds by hand now.  My question arises from the last chemical:  Fungicides.  In central Florida, the summers are so wet that fungus always attacks the grass.  I had to use a fungicide this summer... Are there any non-chemical techniques I can use to eliminate or prevent the fungus during the wet season?

As a side note, if it matters, I irrigate during the dry season with reclaimed water (once again required by the HOA).

Below is a link on some homemade organic fungicides that may help.

http://www.organic-lawn-care-guide.com/organic-fungicide.html

I realize this thread is ancient but others might be looking for the answer. I have been using ordinary corn meal (NOT corn gluten meal) to control brown patch in St Augustine. I apply at a rate of 20 pounds per 1,000 square feet. It seems to work better if you reapply at the same rate after 3 weeks. Apply to the entire lawn so you don't end up chasing it around spot after spot. This will absolutely not work if you have already applied a chemical fertilizer.

Why does corn meal work?
The fungus that decomposes fresh corn meal attracts another fungus called Trichoderma (try ko DER mah). The Trichoderma is a predatory fungus that feeds on other fungi. When it finished feeding on the fungus decomposing the corn meal, it has multiplied in population greatly and goes out looking for other fungi. It finds the disease and wipes it out.

There are a few people whose opinion I respect who have not had the same luck with corn meal as I have. I'm working to figure out what the differences might be between their experience and mine.

Fungus in zoysia is a very serious problem. Once you get a fungus, it kills the surface turf. When that happens it can take 9 months before the zoysia returns. This is one reason you'll see a lot more St Augustine in the south than zoysia.

Its really hard to be with a place that's always changing its weather, especially if there are some things that will be affected. So, it is good to have an advance preparation for every changing of seasons.