On golf courses, the most common problem appears to be anthracnose, a stress disease. Factors that enhance this disease are compaction, low mowing heights, low N, and insufficient water. The sticky spores are easily spread by mowers, feet, etc. To diagnose crown rot, try to pull individual plants out from the turf and look for the charcoal black evidence of the anthracnose fungus at the base of the plant. Anthracnose often appears first in annual bluegrass but can also affect bentgrass.
Red thread continues to plague many lawns.
Another problem that may appear in lawns is melting-out. Melting-out is usually described in textbooks as a disease that develops from heavy leaf spot infections in the spring in prolonged wet weather where lawns have received excessive N fertilizer. Melting-out can also develop during stressful periods when some leaf spot is present, such as areas where a lawn is not sufficiently irrigated. Essentially, the leaf spot fungus overtakes the plant when it is stressed. You may be able to see the reddish-brown lesions of the leaf spot fungus along the length of the leaf blade and sometimes extending into the crown of the plant.