Algae crusts can be a serious nuisance on golf course putting greens. When conditions are favorable, algae crusts can form a thin layer on top of the turf canopy blocking light and impeding the movement of water and air into the rootzone. The pictures in this post came courtesy of Pat Franklin, CGCS, who encountered an unexpected algae outbreak this summer.
Algal occurrence and development is most common during the summer months when high air and soil temperatures result in turf thinning. Algae is most likely to develop in areas of the green which have thin turf cover allowing air, light, and water to reach the thatch surface. Areas with poor drainage and excessive shade further promote algal growth. The presence of phosphorus also encourages the development of algae. Unfortunately, algae can appear in situations where proper cultural practices are the routine and the turf is relatively healthy. The outbreak Pat experienced occurred after a period of wet weather.
So if you find yourself in this situation what is the best way to control algae? The best method of controlling algae is through a preventative management program:
Water- Water management and proper drainage is critical to preventing algae. Remember, algae need surface water to develop and grow so proper irrigation scheduling is critical. Cultural practices such as topdressing and aerification that help keep the upper soil layers dry will also help.
Fertility - Phosphorus appears to be a key component for the development of algae. Using products that lack phosphorus or reducing phosphorus application rates is recommended.
Chemical controls – Although cultural controls help, algae often occurs despite your best efforts. In these situations, fungicides are needed to effectively control the problem. Ammonium sulfate and hydrated lime are effective at “burning” the algae but these products can also very easily “burn” the turf. Chlorothalonil and mancozeb are very effective products and are much safer to the turf. Pat effectively controlled his algae problem with Fore fungicide. If making curative applications, it is recommended to spray on a 7 to 14 day interval at high label rates. The lower label rates may be used as part of a preventative spray program. Additional fungicide applications are often recommended even after the symptoms of algae have disappeared as algae can return quickly if the conditions are favorable.
For more information regarding algae and it control see the following links:
Graduate Research Assistant