Those photos look more like a poor soil condition than an actual pathogen. A saprophyte (decomposing fungus) may not actually attack the turf plant but can affect the soil and present a fungal pattern. Try something simple like arification and wetting agent, There is some new chemistry ( Helena's Reservoir, 5#/1000 @$1/#, $50 for a 10,000 sq ft green) in wetting agents that work as flocculators (sp?) and help create pore space rather than affect the surface tension of the water. Remember the disease triangle. Pathogen, Host, Environment. The pathogens are ubiqutous, can't really change that. The only way to affect the host is to replant with a resistant variety, I doubt if changing out the green is a viable option. Environment though, now we can do something! Change your ways, one at a time, and see what happens. Good luck.