Do you notice brown spots in portions of your otherwise robust lawn? If yes, it may indicate that fungus or turfgrass disease is hurting your lawn. Turf diseases nearly always first emerge as a brown ring or spot in a healthy, green patch of grass. The diseases that attack cool season lawns like ours are worse during the late spring and summer months (May, June, July, and Aug). Excessive moisture from rain or irrigation can intensify these diseases.