Large Areas of Dead Grass in Bluegrass Lawn

I have large brown areas of dead grass in my bluegrass lawn. It seems to turn brown, dry up and disappear. What is it and can I fill in the bare areas with sod this fall?

Helminthosporium leaf spot also called melting out will cause the damage you describe. Cultural controls and reseeding will usually keep this disease under control. Fertilize in fall avoiding heavy spring fertilization. Keep the grass 2 ¹/₂ to 4 inches tall. Healthy lawns are more resistant to this and other diseases. Reseed dead areas with a mix of several disease resistant bluegrass cultivars such as Adelphi, Baron, Eclipse, Nugget, Parade and Touchdown. You may want to overseed your lawn to help build in disease resistance to future infections. Seeding provides a greater selection of grass seed varieties plus newly laid sod may fall victim to the disease.