Hosts
Annual bluegrass (a
common weed in turf), Kentucky
bluegrass, St. Augustinegrass, tall
fescue
Symptoms
Rhizoctonia blight first appears as irregular patches of weakened
grass that may enlarge to many feet in diameter. The affected area
may be a smoky color. Leaves and sheaths are watersoaked, wilted,
and light brown. Fungal threads may be apparent.
Conditions favoring disease
High temperatures (80° to 95°F) and high humidity favor
the development of Rhizoctonia blight. Excess thatch, poor drainage,
and soft, lush growth due to excessive nitrogen also contribute to
disease development.
Prevention and management
Reduce shading and improve soil aeration and
water drainage. Follow the irrigation and fertilization
rates for your turf species. Avoid watering in the evening. Dethatch when
the thatch layer exceeds 1/2 inch (1.2 cm). A fungicide may be useful
if the disease was severe in the past or for seedlings in young turf.
For more information on lawn diseases, refer to:
Pest Notes: Lawn Diseases:
Prevention and Management |
