Diagnosing Problems in the Florida Lawn

Insect and Fungus Management in Florida Turf Grasses

Aug 6, 2009

Use this flow chart to help identify common pest problems such as chinch bugs and mole crickets in St. Augustine grass, centipede grass, and other southern turfgrasses.

The University of Florida Institute of Food and Agricultural Sciences has developed a handy flow chart to help homeowners determine what might be causing dead or dying grass in their landscape. Yellowing, wilting, dead patches, rings and other signs of insect, nematode, fungus or disease can be diagnosed by answering the questions below.

Brown or Dead Grass in a Southern Lawn

1. Did the problem appear suddenly (within a month’s time) and is not a repeat problem from years’ past?

4. Cut the bottom and top off of a large coffee can or similar metal container. Work the can into the sod, then quickly pour in a mixture of 2 gallons of water and 1.5 ounces of dish soap. Do mole crickets rise to the surface?

6. Has the soil been tested recently for nematodes through the University of Florida Extension lab?

7. Does the troubled area appear to occur in a circular ring-shape or are there yellowish margins around the perimeter?

9. If the soil tested negative for nematodes, push a garden trowel into the soil. Is the soil hard?

12. Pull up some grass around the perimeter of the damage and check for chinch bugs. If they are not immediately visible, cut the bottom and top off of a large coffee can or similar metal container. Work the can into the sod, then quickly pour in several gallons of water. Do chinch bugs rise to the surface?

13. Are individual grass blades streaked with red or yellow? Do they eventually turn brown?

14. Sod webworms or other caterpillars can cause damage from mid-summer until frost. Consult the Master Gardeners at a local IFAS Extension office for control recommendations. Squirrels also chew St. Augustine grass year-round, leaving damaged patches with loose blades scattered on the sod surface.

15. The area may not be receiving enough sun. Homeowners can try plugging with St. Augustine grass or another shade-tolerant grass, use a shade-loving groundcover, or simply mulch with Florida-friendly materials such as pine straw, leaves, or pine bark.

16. The lawn may have a fungus, especially if the rings are occurring in summer, fall or winter. If it is early spring, wait until late May to see if the grass simply needs to recover from frost damage or fall/winter pests. Powdery or slimy films on the grass in summer may be a benign slime mold that does not harm grass. These slime molds can be orange, gray, black or tan and can be washed or swept off of the grass if the homeowner wishes. For more serious molds, consult the Master Gardeners at a local IFAS Extension office for control recommendations.

Mole Crickets in the Florida Lawn

17. A mole cricket infestation is defined as 2-4 or more mole crickets appearing in a 2 x 2 foot area. Treat for mole crickets. The Master Gardeners at a local IFAS Extension office can provide treatment recommendations.

18. The lawn may have nematodes. A Nematode Sample Kit can be obtained from a local University of Florida County Extension Office.

19. Compacted soil can inhibit grass growth. Contact a local University of Florida IFAS Extension office for recommendations.

20. It is unclear what may be wrong with the lawn, and the lawn’s decline may be a combination of factors. Follow recommended fertilization, watering and mowing practices for the particular grass type. Other potential causes are take-all root rot or centipede grass decline fungus. Help can be obtained at a local University of Florida IFAS Extension office.

21. Gray leaf spot disease is likely the culprit. Contact the Master Gardeners at a local University of Florida IFAS Extension office for control measures.

Chinch Bugs in St. Augustine Grass

22. Chinch bug infestations are usually worse in sunny areas. Talk to the Master Gardeners at a local University of Florida IFAS Extension office for treatment recommendations.

23. If occurring in summer or fall, the damage could be due to spittlebug. Spittlebugs are black bugs with two orange stripes on their back. Contact the Master Gardeners at a local University of Florida IFAS Extension office for recommendations. Yellowing of the grass in springtime is often due to iron chlorosis which can be corrected with proper fertilization.

If there is still doubt as to the cause of the lawn problem, contact a local University of Florida IFAS Extension office or lawn care professional. The UF Master Gardeners can provide recommendations and solutions that also protect the local environment and water supply.

Note: This information is provided with authorization from the University of Florida's IFAS Extension.

The copyright of the article Diagnosing Problems in the Florida Lawn in Landscaping is owned by Christy Swift. Permission to republish Diagnosing Problems in the Florida Lawn in print or online must be granted by the author in writing.