University of Connecticut
Winter Turfgrass Problems
Steve Rackliffe, Extension Instructor
Department of Plant Science
In the northeast, there are a number of winter turfgrass problems that can negatively affect residential lawn quality. Often winter turf problems may be a result of either winter disease or physiological stress brought about by climatic conditions. Four possible lawn problems that may negatively affect Connecticut lawns in the winter months are: Gray and pink snow mold diseases, and physiological stresses that are brought about by ice and desiccation.
Snow Mold Diseases
There are two snow mold diseases that are of importance to turfgrasses in New England. One is Pink Snow Mold and the other is Gray Snow Mold.
Pink Snow Mold (Microdocium patch)- is a disease that may occasionally infect residential turf. It is of greater concern, and more commonly found, on commercial turf such as golf courses and sports complexes. Of the two snow mold diseases it is the more destructive. Unlike gray snow mold, pink snow mold does not require snow cover to become active. While snow cover favors pink snow mold growth, it can become active and spread during periods of cold wet overcast weather. Symptoms of pink snow usually begin as circular patches with tan centers and pink colored perimeters. In the early stages of the disease, patches will be two to three inches in diameter (figure 1). If left unchecked and favorable conditions continue, the patches may coalesce and form larger patches of three feet or more. Severe infestations of pink snow mold can often lead to the death of turfgrass plants. While chemical control is recommended on sports turf, it is usually not recommended for residential lawns unless damage is severe.
Gray snow mold (typhula spp.)- is of greater importance to residential lawns than pink snow mold. Gray snow mold requires snow cover in order to become active. As the snow begins to melt, areas infected with gray snow mold will exhibit a gray mycelium ("cottony looking") mass. As the area dries and the snow recedes, the patch or symptom illustrates a brown to gray matted area ranging in size from 2 inches to 2 feet (figure 2). Once the disease is present, fungicidal control measures are not recommended as the damage is already done. Gray snow mold rarely kills the complete plant therefore preventative fungicide applications to residential lawns for gray snow mold control are not recommended.
Snow Mold Disease Control
Succulent turf as well as snow cover on unfrozen ground favor both gray and pink snow mold. While we have no control over the freeze and thaw cycles of Mother Nature, we can reduce succulence of the turf in late fall by altering or eliminating fertilization practices. To help reduce the incidence of snow mold, reductions in high rates of nitrogen, and the use of slow release forms of nitrogen in the fall are recommended. To encourage rapid recovery of infected areas, aggressively rake or brush the unsightly matted patches in early spring.
Ice Damage (Figure 3) - while not a disease, ice can present the greatest problem to residential lawns. Extended ice cover of 45-60 days can lead to turfgrass death. The extent of plant death or injury depends on the turfgrass species and the duration of ice cover. Ice problems usually occur in shaded areas or in depressions found throughout the lawn. Once ice damage has occurred there is little that can be done except to replant. However, it is recommended to give the lawn a chance to recover. Often times the top growth can experience die back while the crown and roots remain healthy. To determine if the turf is alive, examine the roots to see if they are white and succulent. Another method would be to take a sample of the infected area, pot it, and place it in a window and try to force it out of winter dormancy.
To reduce the incidence of ice damage, it is recommended to install drainage tiles in low areas of the property to remove surface water. Also, one can select grass varieties that exhibit a higher degree of cold hardiness. For example, Kentucky bluegrass illustrates greater cold temperature hardiness than perennial ryegrass.
Winter Desiccation- Turfgrasses in the northeast may experience damage as a result of desiccation. In Connecticut desiccation is usually the result of atmospheric drought. While winter desiccation can result in complete death of the plant, it is more likely to be superficial and only the top growth experiences “a browning out”. Atmospheric drought may be brought about by uncovered (snow) turf exposed to high winds, particularly on elevated sites. Good management practices that promote root growth will aid in reducing winter desiccation. Where desiccation is a perennial problem, wind breaks such as snow fences may be installed to aid in the prevention of winter desiccation.
Figure 1. Pink Snow Mold (Photo Rackliffe) Figure 2. Gray Snow Mold (Photo Rackliffe)
Figure 3. Ice Damage to Perennial Ryegrass
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Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914 in cooperation with the U.S. Department of Agriculture, Kirklyn M. Kerr, Director, Cooperative Extension System, University of Connecticut, Storrs. The Connecticut Cooperative Extension System is an equal opportunity employer.