Annual bluegrass (a
common weed in turf), Kentucky
Infected leaves, sheaths and stems have circular to elongated brownish
spots with brown centers and dark brown or purple borders. Crowns
and roots have a dark brown rot. Symptoms may occur throughout the
lawn rather than in clumped areas. Plants may die in hot, windy weather,
leaving thinned areas throughout the turf.
Conditions favoring disease
Warm temperatures (70° to 90°F) and high humidity favor
the development of leaf spot. Weakened turf may be the result of
poor cultural practices. Mowing too short and applying high amounts
of nitrogen contribute to the development of the disease.
Prevention and management
Reduce shade and improve soil aeration and
water drainage. Follow the recommended
irrigation requirements for your turf species and avoid excess nitrogen
fertilizer. Maintain as high a mowing
cut as possible. Fungicides are available but usually are not
warranted for the home lawn.
For more information on lawn diseases, refer to:
Pest Notes: Lawn Diseases:
Prevention and Management