University of FloridaSolutions for Your Life

Download PDF
Publication #ENY-322

Ground Pearls1

E. A. Buss2

Ground pearls are scale insects that suck fluids from the roots of bermudagrass, bahiagrass, St. Augustinegrass, and zoysiagrass, but prefer centipedegrass. They may be associated with acidic soil. They occur throughout Florida.

Damage

Symptoms attributed to 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 tolerate ground pearl feeding damage, and the grass may die. There are other factors, such as disease, nutritional imbalances, drought, and nematodes (especially in centipedegrass) that can cause off-color areas in lawns. The lawn should be carefully examined to determine what corrective measures are needed. Weeds tend to invade infested areas.

Life Cycle

Clusters of pinkish-white eggs, covered in a white waxy sac, are laid in the soil from March to June. Tiny crawlers or nymphs attach to roots and cover themselves with a hard, yellowish to purple, globular shell (Figure 1). These “pearls” range in size from a grain of sand to about 1/16 inch. They may occur as deep as 10 inches in the soil (Figure 2). The adult female is 1/16 inch long, pink in color, with well developed forelegs and claws. Adult males are rarely seen, tiny, gnatlike insects. Females emerge from cysts in the spring, move around a little, then dig several inches into the soil and secrete a waxy covering. One generation may last from one to two years.

Figure 1. 

Ground pearl feeding on a root.


Credit: J. Castner, University of Florida
[Click thumbnail to enlarge.]

Figure 2. 

Ground pearls collected in soil (match stick used for size comparison).


Credit: J. Castner, University of Florida
[Click thumbnail to enlarge.]

Management

No management strategies, including biological and chemical controls, are currently available for ground pearls. Minimize plant stress and maintain proper fertility and irrigation to help grass tolerate the damage. Properly watered and otherwise well managed lawns often do not show noticeable damage, even though they may be heavily infested with these insects. Removal of the top few inches of soil or killing the grass with herbicide in an infested area are also not enough to reduce ground pearl infestations. The waxy coating surrounding the insect helps it to survive almost any adverse condition. One viable alternative is to redesign the area without grass to eliminate the ground pearls' food source.

Footnotes

1.

This document is ENY-322 (LH073), one of a series of the Department of Entomology and Nematology, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Date first printed: October 1993. Revised: June 2008 and July 2011. Please visit the EDIS website at http://edis.ifas.ufl.edu.

2.

E. A. Buss, associate professor, Entomology and Nematology Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.