Help!! Need advise. I seeded .3 tenths of acre of lown this spring. ( Used a slit seeder) Good stand of mixed grass. Lot of rain did not water. Has been dry and hot the past 3 wks. I have some brown rusty looking patches showing up in the grass. Is this a fungus? My black mower deck almost red now with rusty stuff. I live in NW Ohio. What do I do? Or will this go away without treatment?