This is the toughest time of year for courses that overseed bermudagrass fairways and rough during winter. The transition from overseeded perennial ryegrass back to bermudagrass is not always as smooth as golfers would hope. The hot, humid weather in recent weeks has accelerated the decline of any remaining perennial ryegrass. In addition to the heat, there are several other factors weakening the overseeded turf including:
- Fungal diseases such as summer patch, rapid blight, anthracnose, southern blight and gray leaf spot
- Infestations of various white grub species
- Elevated soil salinity
- Drought stress
With each year of overseeding, it is typical to experience a 10-percent decline in the amount of bermudagrass base. Eventually, after several consecutive years of overseeding, there may be very little bermudagrass left, resulting in dead spots and bare areas when overseeded perennial ryegrass begins to die out during summer. The solution for most golf courses is to re-establish previously overseeded areas with improved varieties of bermudagrass and discontinue the practice of winter overseeding.
USGA-funded research is underway at the University of California, Riverside, to develop bermudagrass varieties that retain winter color. Improved winter color retention could eliminate the desire to overseed bermudagrass during winter. A progress report on the research will be highlighted at the upcoming University of California Cooperative Extension Turfgrass and Landscape Research Field Day on Thursday, September 14.
West Region Agronomists:
Patrick J. Gross, regional director – pgross@usga.org
Larry W. Gilhuly, agronomist – lgilhuly@usga.org
Brian S. Whitlark, agronomist – bwhitlark@usga.org
Information on the USGA’s Course Consulting Service