Now is the time of year, when our lawns begin talking to us. Showing us signs if something is wrong. Basically – the lawn wants and needs your help. Perhaps you have a patch of brown, gray or yellow and it’s shaped like solid circles or outline rings or, is it more like a series of spots or splotches? Whatever the case, chances are it’s fungi. Be observant and listen to your lawn.
In our state, most lawn diseases are caused by fungi. However, some problems that resemble disease can have the same symptoms – such as, wilt, excess salts, soil compaction, and chemical damage. So, it’s very important to identify the real cause and treat it appropriately.
Fungi are microscopic-organisms but, there are points in their lifecycle when they can be viewed with naked eye. You might see –
- Mycelium – a cottony or spider-web-like mass of fungal growth that certain fungi produce when the turf is wet or humidity is high.
- Spore Masses – fuzzy or jelly-like growths produced on the diseased tissue by certain fungi, again usually when the turf is wet or humidity is high.
- Pustules on Leaves – small, spherical structures produced on the leaf surfaces, that contain fungal spores.
- Blisters on Leaves – raised areas of leaf tissue that change color and then rupture to release powdery masses of fungal spores.
- Fruiting Bodies – structures of various shapes and sizes that release fungal spores. Usually dark in color and embedded in the diseased plant tissue. May be found on all above- and below-ground parts of the turf plant.
- Sclerotia – small, round, or threadlike structures produced on the diseased turf or in the thatch layer by certain fungi.
- Puffballs – A spherical spore-producing structure up to 3″ in diameter produced on the turf surface. Similar to a mushroom, but lacking a stem or stalk.
- Mushrooms – Spore-producing structures with a cap and stem produced on the turf surface by Basidiomycete fungi.
Some of the more common forms of turf disease in the Piedmont Triad include the following (all are caused by fungi) –
Brown Patch A disease caused by the Rhizoctonia fungus is common in bentgrass, bluegrass and tall fescue. Develops on moist foliage in hot, humid weather with daytime temps above 85°F and nighttime temps above 60°F. Other factors that favor brown patch are – lack of air movement, cloudy weather, dew, overwatering, excessive nitrogen, and too little potassium & phosphorus.
Copper Spot A disease caused by the Gloeocercospora sorghi fungus occurs in bent grass and bluegrass. Small spots, usually less than 3″ in diameter, appear that are copper or salmon in color. When the turf is wet or humidity is high, the infected leaves may be covered with a thin, gelatinous coating of fungal spores.
Dollar Spot A disease caused by the Sclerotinia homoeocarpa fungus occurs in all turfgrasses. On a putting green, small spots, the size of a silver dollar, appear bleached-white or light tan in color. On turf mowed at heights greater than 0.5”, the spots may expand in size up to 6” or more. The grass in the spots may be killed to the soil surface. Short, fuzzy white mycelium is often observed in the morning when dew is present.
Fairy Ring A disease caused by Basidiomycete fungi that lives underground seasonally marked by a ring of mushrooms occurs in all turfgrasses. Growth of these fungi in the soil can indirectly affect, or even kill, the turfgrass above. Don’t be fooled by folklore, these rings weren’t made by dancing of fairies and they don’t bring good fortune.
Gray Leaf Spot A disease caused by Pyricularia grisea fungus occurs in ryegrass and tall fescue infecting and killing the leaf blades. Small, gray lesions appear on leaves in warm, humid weather. The lesions widen and become round or oval spots with a tan center and purplish margin.
Pink Snow Mold A disease caused by Microdochium fungus occurs in bentgrass, ryegrass, bluegrass and tall fescue. It develops during periods of snow and exhibits symptoms as the snow melts. It also can infect turfgrass without snow during periods of cool, wet weather. Then, it’s called Microdochium Patch. Both appear as white or light tan circular patches from 2” to 1’ with a pinkish ring or growth present.
Spring Dead Spot A disease caused by Ophiosphaerella fungi occurs in bermudagrass and zoysiagrass. Circular patches from 6” to several feet that remain dormant as the turf greens up in the spring then, eventually dies and collapses to the soil surface. The patches recur in the same place each year, increasing in size each season.
This is only a sampling of the fungal diseases that can impact your lawn.
As mentioned earlier, it’s very important to identify the real cause of the problem and treat it appropriately. Doing nothing or, choosing the wrong course of action could exasperate the problem.
If you suspect that you have a turfgrass disease, please contact our office immediately so we may come and accurately diagnose the problem.
Inspiring You to Love Your Lawn!
For more information on turf diseases – visit http://turfdiseaseid.ncsu.edu/ or, http://www.ipmcenters.org/pmsp/pdf/NC-VAturfgrass.pdf