Algae are primitive green plants. They can be a problem on turfgrass when surface conditions are overly wet. They tend to occur in low, shaded, or compacted areas. Algae form a greenish to black scum on the soil or in thin turf. As this blackish scum dries, it appears as a crust that later cracks. Turfgrass plants may become chlorotic (yellowed), weak, and eventually die.
Algal scums can be controlled by:
- improving surface and subsurface drainage
- avoiding frequent waterings, especially at night
- aerifying compacted areas
- maintaining proper pH and nutritional levels
- increasing mowing height
- improving light penetration to turf
- using shade tolerant grasses in shady areas
Algacides or fungicides can help control algae problems when wet conditions are also corrected. Fungicides such as Daconil 2787 or Algaen-X are labeled for control of algae. Other fungicide type materials, such as applications of dilute solutions of liquid household bleach or copper sulfate (2 to 3 oz. per 1000 sq. ft.), are noted to control algae when used with cultural practices. Caution should be used. Excessive rates are toxic to grass plants.
This article originally appeared in the May 10, 1996 issue, p. 71.