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Ground Pearls in Turfgrass 1
E. A. Buss2Ground pearls are scale insects that attack the roots of bermudagrass, bahiagrass, carpetgrass, St. Augustinegrass, and zoysiagrass, but prefer centipedegrass. They suck juices from plants, which makes irregular patches of grass look unhealthy. Grass yellows, browns, and dies, especially in hot, dry weather. Weeds tend to invade infested areas. They occur throughout Florida.
Biology and Behavior
Clusters of pinkish-white eggs, covered in a white waxy sac, are laid in the soil from March to June. Tiny crawlers 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 rare, tiny, gnat-like insects. One generation may last from 1 to 2 years.
CREDITS: J. Castner, University of Florida
Figure 1. Ground pearl feeding on a root.
CREDITS: J. Castner, University of Florida
Figure 2. Ground pearls collected in soil (match stick used for size comparison). Detecting Infestations
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. On the other hand, properly watered and otherwise well managed lawns often do not show noticeable damage, even though they are heavily infested with these insects. There are other factors such as disease, nutritional unbalances, 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.Control
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.
Footnotes
1. This document is ENY-322, 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 2005. Please visit the EDIS Web site at http://edis.ifas.ufl.edu.2. E. A. Buss, assistant professo, Entomology and Nematology Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611.
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U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Larry Arrington, Dean.
Copyright Information
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