Seven Lawn Diseases and How to Treat Them

Taking care of your lawn is a full time job. In the spring you thatch and fertilize, in the summer you mow, in the fall you fertilize, and in the winter you worry about it. If your lawn comes down with a disease, it can be extremely disheartening. You put so much work into it and now it looks terrible. You shouldn't be hard on yourself, though. Most lawn diseases are difficult to prevent, and even some of the best maintained lawns can get diseases.

In my time as a landscaper, I ran across a lot of different lawn diseases, but for this article I am including the seven most common that I encountered. I'll let you know what they look like and what can be done about them.

7) Powdery Mildew. This disease looks like white paint or powder on the tips of grass. It occurs almost exclusively in moist, shady areas. If you run your finger along the grass, some of the powder will come off on your fingers.

This disease is generally not very serious and can be controlled by getting more light to the grass. If that is not possible, there are commercial preparations like Epsoma disease control spray. It is cheap, made with natural ingredients, and effective.

6) Rhizoctonia Blight. Once known as brown patch, I have only seen a few cases of this since I live in Michigan where it never gets horribly warm in the summer. Rhizcotonia Blight thrives in high heat and forms patches of a couple feet in size. The patches are tan or brown and can have a grayish border.

Thatching and avoiding fertilizing during hot weather will help avoid this, but if you should get it, there are many inexpensive fungicides available, such as Bayer Fungus Control for Lawns.

5) Yellow Patch. This is a bad, bad disease due to the fact that there is no fungicide that is effective against it. It presents as a circle of yellow grass of a couple inches that sometimes has green grass growing with it. This usually occurs in cool, damp weather.

As there is no commercial treatment for this condition, your only option is to reduce thatch, aerate, water less, and keep from fertilizing too heavily in the spring. It may take years for your lawn to completely recover from this, and I have had cases where I was called back to treat it again after it seemed to be gone.

4) Typhula Blight. Also called gray snow mold, this shows up when the snow thaws. It looks like a yellowish patch that is pretty similar to fusarium patch, but can be bigger(sometimes around 3 feet)and can sometimes have a grayish film over it.

To stop this disease you need to be active in taking care of any thatch or leaves that may be on your lawn in the fall. Simply raking this stuff away will drastically cut down on the chance of the fungus. Also, mowing your lawn during the late fall will help. Fungucides are generally not recommended to treat this disease.

3) Fusarium Patch. Formerly called pink snow mold, this disease appears after the snow thaws in the spring. It is caused by a fungus that can thrive in cold weather. It appears as yellow patches of less than a foot in size and can look pink at times due to a filmy cover of mold that can be seen on top of it.

To prevent this disease you should keep your lawn mowed short in the fall and make sure that if you apply fall fertilizer that you don't do it too late in the season. Fungicide treatment is not recommended, as proper lawn care in the fall is the most effect treatment.

2) Dollar Spot. Also sometimes called Sclerotinia, dollar spot is a fungal disease characterized by small(about 6 inches or less) yellowish patches that will sometimes have a red-brown border. It mostly affects bluegrass but also appears in larger patches on bentgrass(which is commonly found on golf courses). It usually appears at higher temperatures when the soil is dry.

The best way to treat dollar spot is through weekly application of a nitrogen fertilizer and plenty of watering. This will usually solve the problem, but if it doesn't there are plenty of inexpensive fertilizer's like Scott's Fungus Control that will work well.

1) Summer Patch. One of three diseases formerly called Fusarium Blight, this disease is probably the most easily spread disease I have run across. It is characterized by yellow blotches of about a foot in size. It tends to occur at times of high heat and is very expensive to get rid of, since the best fungicide to deal with summer patch(called Heritage) costs about $200 for 4 ounces.

If your lawn is covered in patches, you may consider purchasing some Heritage and treating it yourself. The other option is to contact a lawn care services or landscapers and ask around for the best price. Once it is under control, watering and aeration is important along with fertilizer. Making your grass as strong as possible will help it resist this fungus.

In my time as a landscaper I have seen all these lawn diseases effectively treated, with the possible exception of yellow patch, as it tends to recur. It may take time, effort, and occasionally some money, but if you follow the above suggestions you should eventually see success. There are cheaper alternatives, like Ferti-lome F-Stop lawn fungicide, which may help if the disease is in its early stages.