Summer patch
Magnaporthiopsis poae
A root-infecting disease producing frog-eye patches during hot weather, though infection begins earlier.
Identification
Circular straw-colored patches 8–30 cm, often with green tufts in the center ("frog-eye"). Roots and crowns are darkened and rotted.
Symptoms
Patches or rings, yellow/orange leaf blades, tip dieback. Annual bluegrass may die and bentgrass will fill in voids. When found in Kentucky bluegrass, weeds often encroach into patches forming a frog-eye appearance.
Signs
Perithecia (rare), hyphae on roots, cessation structure on the crown when you pull back younger leaves.
Biology
Magnaporthiopsis poae is a soilborne fungus that infects the roots and crowns of Kentucky bluegrass and fine fescue. It is the number one disease of Kentucky bluegrass.
Epidemiology
Summer patch is a summer disease that starts when soil temperatures reach 65 degrees Fahrenheit in the spring. It is most prevalent in newly established or stressed turfgrass.
Favorable Conditions
High soil temperatures (>28°C), high pH, compaction and wet soils; infection occurs in spring/early summer.
Cultural Management
To control summer patch, cultural practices such as using ammonium sulfate to acidify the soil and managing stress on the turfgrass can be used.
Further Reading
University extension resources — open in a new tab.
Related Reports
No published reports yet for this pest.
Reports will appear here as they are peer-reviewed and published.