Summer patch

Roots, crowns, and stolons are affected by a dark brown rot. Young roots may appear healthy, although dark brown hyphae may be present on these tissues. Vascular discoloration and cortical rot occur in later stages of the disease. On occasion, patches may retain centers of green, apparently unaffected grass.

Conditions for Development Root infection is initiated when soil temperatures exceed 65°F; however, foliar symptoms of summer patch are favored by temperatures over 85°F during the day and over 70°F at night. It is also commonly found in areas with high soil moisture, compaction, poor drainage and low mowing height. This disease is typically more severe in turfgrass that has been fertilized with nitrate-nitrogen. Control Measures Use acidifying fertilizer. Increase the height of cut. Reduce soil compaction through aerification and by using lightweight equipment. Syringe when the temperature is over 85°F. Improve the drainage of the turf. Convert from fine-leaf fescue to tall fescue, bentgrass or perennial rye.