I've had the lawn for 6 years with no problems, however this year I am having large and growing areas (15-20ft) of die off. blades lost all color and are straw like. I have put fungicides, insect killers, and nematodes, but the areas keep expanding. some increase by a foot a day. I've treated for sod webworm, grubs,mole crickets, chinch bugs. I've used organocide, fertilome, scotts fungal control, yet nothing is working.

the one thing I have noticed is given enough time, water and fertilizer in affected areas it will SLOWLY and scarcely / thinly come back. Any help would be appreciated