Ground Pearls
CAUTION: This information was developed for North Carolina and may not apply to other locations.
Ground
pearls belong to a family of scale insects. Ground pearls are identified by the
presence of small pearl-like bodies on the roots or in the soil. The pink adult
stage that crawls is present during early summer. The adult female ground pearl
is a wingless, pinkish scale insect, about 1/16 inch long with well-developed
forelegs and claws. The male is a gnat-like insect smaller than the female, but
with a slender waxy "tail"
up to 1/4 inch long. Clusters of pinkish-white eggs are laid in a white waxy sac.
Commonly referred to as a ground pearl, the slender nymph is covered with a hard,
globular, yellowish-purple shell. Encysted nymphs are up to 1/16 inch in diameter.
BIOLOGY
Ground pearls are potentially serious problems in both southeastern and southwestern
states. The roots of Bermuda-, St. Augustine-, zoysia-, and centipedegrasses
are most commonly infested with ground pearls. Ground pearl nymphs extract juices
from underground plant parts. Attack to the roots may cause circular dead areas
that resemble fairy ring. The damage is most apparent during dry spells as irregular
patches of grass turn yellow. The grass in these spots eventually turns brown
and usually dies by fall. The spots enlarge each year and only weeds grow in
the infested areas. Overwintering takes place in the pearl stage. Females usually
mature in late spring and emerge from their cysts. After a brief period of mobility,
females tunnel 2 to 3 inches into soil and secrete a waxy coat. Within this
protective covering, females develop eggs (without mating) and deposit them
throughout early summer. Approximately 100 eggs are laid by each female. The
slender nymphs emerge in mid-summer and infest grass rootlets. Once they initiate
feeding, nymphs soon develop the familiar globular appearance. There is usually
one generation each year. However, if conditions are not favorable for emergence,
female nymphs may remain in the pearl stage for several years.
CONTROL
When establishing new turf with sod or sprigs, check the roots to avoid planting
infested grass.Watering, liming and fertilizing as prescribed by a soil test,
proper mowing height with a sharp blade and other good cultural practices may
help lawns recover from ground pearl injury, but such recovery may be temporary.
No insecticide is specifically labelled for ground pearl control. While university
testing procedes, maintaining healthy, vigorous lawn in hopes of minimizing
damage is the recommendation. Other warm season types of turf, such as bermudagrass,
carpetgrass (Axonopus spp.) or bahiagrass, appear to be less sensitive
to ground pearls and should be considered for lawns with severe ground pearl
problems.
Recommendations for maintaining healthy turf may be found at this TurfFiles site. More information on ground pearls may be found in the turf publication AG-286. For additional information on insect control and pesticide use Contact your county Cooperative Extension Center .
Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by the North Carolina Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage and examine a current product label before applying any chemical.
Prepared by: S. Bambara & Rick Brandenburg, Extension Entomologists
Published by North Carolina Cooperative Extension Service
Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University at Raleigh, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.
ENT/ort-64 July 1994 (Revised) June 2002
Web page last reviewed January, 2011 by webperson.