Hello, I live in Hagerstown. I fully sodded my yard Nov. 2014. It is about 1600 sq ft. There has been moderate shade, but I am removing some trees. The lawn was very healthy except scattered dead grass from the dog urine (2 dogs) during the winter/snow. I first noticed a white, powdery coating on the grass blades around Sept./Oct. Concurrently, several smaller areas (about 8x8 sq ft) thinned significantly and basically died, especially near the edges of the yard. Over time there seems to have developed thatch and lots of brown, curled dead grass throughout entire yard. I have fertilized the yard three times in 2015 with Milorganite and overseeded once around Oct. 2015. I am afraid the grass may continue to die over the winter if I don't address this. I don't know if a fungicide would be appropriate or if it's a soil problem. Your assistance of diagnosis or direction is very much appreciated.
Fungicide applications are appropriate before the fungus infects the plant, this would not be a good time to apply a fungicide. The disease in question appears to be powdery mildew, a common disease of turf grown in shaded areas with poor air circulation. Culturally you can allow more light to enter the lawn and raise your mowing height to at least 3" and avoid high amounts of nitrogen. Limit the amount of nitrogen for a shady lawn to about 2-2.5 pounds per year.Core aeration will help re leave compaction caused by the dogs and also serve as a seedbed for overseeding. Seeding can be done anytime in conjunction with aerating, use a shade tolerant bluegrass cultivar.