How to Identify Turf Disease

Yellow patch of grass

Michael Krinke / Getty Images

A lot of microbes love to make a home in your yard. It's hard to fight back when you don't know which microbe to blame. No wonder Google searches for "lawn disease pictures" are so numerous.

Several universities and organizations supply great pictures of diseased lawns online. Pictures may not be enough, unfortunately—many diseases and insects leave look-alike damage, at least to the untrained eye. The month of occurrence, recent weather conditions, location, soil, and especially turf type all help determine the possibilities.

Identifying the Turf Type

It's crucial to know what grass species make up your lawn. It's almost always a mix of species—all selected for the local climate and soil. Here are several ideas to help determine what type of grass you have:

  • Check the back of the leftover grass seed bag or visit the garden center or website where you purchased the seed to read the contents of the seed mix. Seed companies almost always list the varieties in the mix.

Lawn Disease Identification

The Departments of Crop Science and Plant Pathology at North Carolina State University created a website for turf disease identification using simple checkboxes. Here's how you can step through the process:

  • First, choose (or guess) the grass varieties in the affected lawn and check the month when symptoms appear. These two choices lead to additional tabs, where you can check off symptoms.
  • As you refine the selection criteria, the disease list narrows. Each disease has an easy-to-read information card and clear photographs that help distinguish the symptoms.
  • If you don’t know the grass varieties in the lawn, you can still click through the disease list and look for symptoms and photos.

Also, visit Michigan State University's Turf Disease identifier. This site asks whether the turf is located at a home or golf course, offers checkboxes for 13 symptoms, then asks for irrigation status, time of year, and host plants. 

Both of the NC State and Michigan State sites help demystify a lot of hard-to-identify turf problems. 

Not Just for Turf Pros is targeted to turf professionals who manage golf courses and athletic fields. Luckily, the rest of us can also benefit from the detailed pictures this site offers. There are diagnostics for cool season and warm season turf afflictions as well as technical information on how to help your yard thrive once again. This site also supplies regional turf disease information. 

Take advantage of these expert resources if you want to grow a dense, healthy lawn. It's the best way to avoid lawn weeds and excessive pesticides. 

Article Sources
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  1. Turfgrass Diseases: Quick Reference Guide. UGA.

  2. Turffiles. North Carolina State Extension Website

  3. Turf Disease. Turf Disease Organization Website