Posted originally at Indiana Living Green in July, 2008
Recently, there has been a spate of queries about lawn care and disease.
A woman wrote and sent photos to the Marion County Master Gardeners (marionmg@purdue.edu ) to ask about the brown areas on her lawn. The condition was diagnosed as the disease dollar spot. With dollar spot (Sclerotinia homoeocarpa), you usually see a tan band with a reddish border on a green blade of grass.
This is a common condition that may occur with heavy rains, such as we’ve had the last few weeks, explains Steve Mayer, a horticultural educator at Purdue University Extension in Indianapolis.
Heavy rains wash the nitrogen through the soil faster than usual. Low nitrogen may allow this fungus disease to sprout. If there is low fertility or a lack of fertilizer, the disease may show up in the lawn.
A program that fertilizers the lawn on a regular basis can usually control dollar spot. However, this is not a case of more is better. There are other diseases caused by too much nitrogen, such as brown patch, Pythium blight and leaf spot. Too much fertilizer also increases mowing duties and contributes to run off and pollution in waterways.
If your lawn has dollar spot and you have not applied fertilizer in the last four weeks, apply a half rather than a full-rate now. Always read and follow the label directions of the product you use. Keeping the lawn at 3 inches tall also will help the grass recover, Mayer said.
For more information:
- about dollar spot.
- Purdue’s publications about the care and maintenance of lawns.
- For Mayer’s info on how to prevent lawn disease
