In mature centipedegrass lawns (3 or more years old) problem areas appear
in the spring and enlarge throughout the summer. These problem areas usually
develop in thatchy turf, compacted soils, droughty spots or areas under
some other stress. Since a specific disease organism has not been identified
as the causal agent, the problem has been broadly named "centipede
decline".
Symptoms. Centipede decline is descriptive of the problem as the
grass gradually deteriorates and is replaced by weeds or other grasses.
Frequently, the grass greens up in early spring and gradually turns off
color, wilts and dies. These areas may initially be less than 1 foot in
diameter, but by mid-summer may have expanded to 3 to 6 feet in diameter.
Individual areas may coalesce to produce large irregular shaped patterns
of wilted and discolored turf. Such areas resemble centipedegrass suffering
from drought conditions.
Examination of turf in these declining areas reveals very little root development.
In fact, many of the stolons, or runners, have no root attachment to the
soil. Some small discolored roots may be found in the thatch, or the organic
layer. The grass may be dead in the center of the area with discolored,
often dark green, leaves radiating into the healthy grass.
Control. Cultural practices provide the most effective means of preventing
centipede decline. Mowing heights above 2 inches tend to promote centipede
decline; while mowing heights of 1° inches or less at weekly intervals
lessen the problem. Mowing height does not provide absolute control, but
reduces the potential for centipede decline.
Application of nitrogen at rates above 2 pounds per 1,000 sq. ft. per year
has been shown to increase problems with centipede decline. Ideal N fertilization
of centipedegrass would be 0.5 pounds N per 1,000 sq. ft. in April, June,
August and October.