Last year i had the most beautiful grass on th eblock. new lawn only 2 yrs old. this spring i've had dying spots in certain areas but other spots are as thick and green as ever. power raked it to remove thatch (had about 1/2 inch) always mulch when mowing, fertilized it and everything but grass was still dead. checked for grubs and insects and nothing as far as i could see. any ideas. ????
I know you said you checked for grubs, but... your pics look exactly like what we had. And it was grubs. I'm not an expert, and there's likely 10 reasons this could occur; just saying pics look exactly the same. Maybe look again in multiple areas for some of the nasty little buggers?