Symptoms. Round-to-irregular patches of grass may look as if they are covered with a slimy, creamy-white or greasy-black substance. This will quickly become a powdery white, gray, bluish-gray, tan-to-orange, purplish-brown, or black covering which can easily be rubbed off. Individual leaves can be covered with large numbers of pinhead-sized, fruiting structures of the fungi.
The affected patches of turf can be up to two feet across. Except for the fungal growth the grass is unaffected. It does not usually turn yellow or die. If the leaves are almost completely covered by a heavy infestation, some yellowing and weakening of the plants may occur. These plants may become more susceptible to other, pathogenic, fungi.
In a week or two, the fungal growth usually disappears. It will often reappear in the same place each year.
Life cycle. These fungi spend much of their lives as colorless or white, shapeless, slimy masses. They move from one place to another by "flowing" over the soil surface, thatch and plant surfaces. When they are ready to reproduce, they flow up the stems of grasses and produce the colored, pinhead-like structures. Spores are produced in these. The spores are blown, carried, or splashed to new plants, where they will grow and eventually merge with each other to form the shapeless, slimy mass.
Prevention. There is usually little reason to control these fungi, as they cause minimal damage.
Chemical control measures are not usually necessary. Check current recommendations.
By Pamela S. Mercure, IPM Program Assistant, University of Connecticut, 1998.
References.
Smiley, R.W. 1983. Compendium of Turfgrass Diseases. APS Press, St Paul, MN.
Smith, J.D., N. Jackson, and A.R. Woolhouse. 1989. Fungal Diseases of Amenity Turfgrasses, Third Edition. E. & F.N. Spon, London.
Turgeon, A.J. 1996. Turfgrass Management, Fourth Edition. Prentice Hall, Upper Saddle River, New Jersey.
This information was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.
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