here i saw this on google someone else was wondering the sam thing and this is what they said to do
The tried and true organic solution to resolving fungal disease (almost any fungal turf disease) is to use ordinary corn meal at a rate of 20 pounds per 1,000 square feet. It takes 21 full days to improve but then, suddenly, it looks better. This is not a home remedy or tonic. The research was started at Texas A&M University at Stephenville back in the 90s. You can use grocery store corn meal or I get it in 50 pound bags at the local feed store for about $6.
Corn meal works by stimulating the growth of the Trichoderma (try-ko-DER-ma) family of fungi which, in turn, kills most of the popular lawn fungal diseases without hurting the rest of the soil microbial populations. The process of feeding the Trichoderma and killing the disease is what takes 3 weeks.
Corn meal is also an organic fertilizer, so if you use it for fungus, you won't need to fertilize any time soon.