“Patch diseases” can be very destructive when Kentucky bluegrass is grown under intensive management. Two patch diseases with similar symptoms can occur. Necrotic ring spot often appears in early summer. Summer patch, the more common disease in Kentucky landscapes, develops in middle to late summer.
These diseases are often a concern in lawns under intensive management for two reasons:
- Improper application of certain lawn management practices, such as close mowing, can aggravate disease development.
- When a lawn receives significant inputs of fertilizer and irrigation and frequent mowing, the homeowner or landscape manager usually has high aesthetic expectations and tolerates little turf damage.
Vincelli, Paul C. and Powell, A. J. Jr., "Patch Diseases in Kentucky Bluegrass Lawns" (1996). Agriculture and Natural Resources Publications. 60.