Pythium and Dollar Spot Lawn Diseases

Every vigilant homeowner knows that, when it comes to maintaining a healthy lawn, you’ve got to understand the problem you’re facing in order to treat it effectively. But

here is the tricky part: many lawn diseases look very similar in the way they affect your turf.

It can be very difficult to determine what disease has overtaken your lawn, simply based on how it looks. Like many others, pythium and dollar spot disease can look very similar when they first infect your grass.

Let’s take a look at how to differentiate the two, and how to eradicate them:

Pythium Lawn Disease

This disease tends to attack cool-season grasses, so it’s somewhat less of a threat to North Texas lawns. However, it’s still good to know what to look for, especially if you have a mixed grass bed that includes both warm- and cool-season grasses.

Pythium lawn disease prefers hot and humid weather, making it a great candidate for North Texas springs and summertime. It initially appears as  small spots on your grass blades. These will quickly turn to spots or patches in your lawn, which is what makes it easily mistaken for dollar spot disease.

However, pythium will eventually elongate in its growth patter, creating streaks of dying grass that include dried and shriveled blades. They may look grey or light brown, and might have a white-ish webbed appearance in early morning light.

As for prevention and protection, a well-drained lawn with good aeration is your best bet. Be sure to check your soil’s mineral balance and be sure it isn’t too nitrogen heavy. Ammonium sulfate, as well as fungicides, are helpful in both killing and preventing pythium lawn disease.

Dollar Spot Disease

This fungus is different from the others, in that it only affects the blades of your grass, but not the roots or stolons. Nevertheless, it can make for a very unattractive lawn, so it is to be avoided.

The disease prefers high temperatures and humidity, just like pythium lawn disease. And it shows up initially in small round yellowish spots. As stated before, this is what makes it initially difficult to differentiate the two.

However, dollar spot disease will continue to spread in spotty clusters rather than elongating. In some cases, the grass blades may turn from yellow to a rusty brown color.

Unlike pythium disease, dollar spot enjoys low-nitrogen soil, which means that adequate fertilization practices can help minimize the occurrence of this disease in North Texas lawns. Adequate watering and drainage, provided in a way that keeps the soil moist but doesn’t oversaturate the grass blades, is best practice. Fungicides are also helpful in avoiding dollar spot disease.

If you’re looking for more information about common fungal diseases in North Texas, check out our all-inclusive article on North Texas lawn diseases!