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TONY MELTON: Hundreds of yards devastated by ground pearls

August 19, 2018

People from all over the Pee Dee call me when they have problems with their yard. Therefore, I look at hundreds of ugly yards each year.

First, I ask the owners how they maintain their lawn. Most of the time, the problem is caused by what they have or have not done. As Pogo would say, “We have met the enemy - and he is us.” Sometimes we bring the problems to our yards.

One such problem is ground pearls. In fact, I have personally seen hundreds of yards in the Pee Dee devastated by ground pearls.

Ground pearls are insects that feed on the roots of grass. They are called ground pearls because they resemble pearls. You can see them. To determine if you have Ground Pearls, take many samples of soil from the green grass at the edge of the dead grass. Stir the soil in your hand in the bright sunlight. Ground pearls will look like little pearls shining in the sun. To tell ground pearls from sand and other debris, crush them in your fingers and they will pop.

It’s not a very pretty situation when you have ground pearls. The symptoms of ground pearl injury are first a yellowing of the grass, followed by browning. Ground pearl damage becomes most noticeable when the grass is under stress due to drought, nutritional deficiencies, etc. Under stress conditions, the grass may not be able to withstand the added effects of the pearls and the grass will die. Centipede is aggressively attacked by ground pearls simply because it is not very competitive or vigorous. Bermuda grass is much more competitive and will live fairly well for a few years even when attacked by ground pearls.

There are some insecticides registered for ground pearl control on home lawns and usually contain bifenthrin, carbaryl, or a combination of chlorantraniliprole and bifenthrin. However, to quote Clemson’s turf entomologist Dr. J.C. Chong, “The fact that some products are registered for the management of certain pests does not mean that the active ingredients of those products are indeed effective against those pests.” In his research J.C. has found little hope but research is ongoing in the southern U.S. to identify insecticides that may be effective against ground pearls.

At present, the only widely accepted recommendation to control ground pearls is never bring them to your yard. Once they are in your yard you are out of luck. From that point on you will have a hard time growing any type of grass.

This is one of the reasons, I never bring soil from other yards or topsoil into my yard. Pure washed sand, since it is almost sterile, is the only soil I will bring into my lawn. Some individuals in the Florence area have tried removing and replacing the top layer of the soil to get rid of ground pearls. Because ground pearls can be found almost a foot deep in the soil, the removal of a few inches of topsoil is not adequate.

Ground pearls mostly damage grass and don’t seem to damage most shrubs, trees, perennials, etc. In some lawns alternative plantings may be the only solution. My former boss has this problem and has given up on growing grass. Along with alternative plantings of shrubs, he is trying a groundcover like mondo grass or liriope and mows it to resemble a lawn grass.

The Clemson University Cooperative Extension Service offers its programs to people of all ages, regardless of race, color, gender, religion, national origin, disability, political belief, sexual orientation, gender identity, marital or family status and is an equal opportunity employer. Email Melton at amelton@clemson.edu.

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