• Latin Name: Margarodes Spp.
  • Latin Family Name: Margarodidae
  • Common Name: Ground Pearls
  • Other Names: Earth pearls, Pearl scale

Origin:
Some species likely native to North America, but others found in Australia. In the U.S. they have been found in the southwest states and the southeast states.

Biology:
These are very odd species of scales, living completely underground and feeding on the roots of plants. The insect secretes wax that forms a shell that completely encloses the insect except for its mouthparts. Movement and spread occur when the adult female emerges from her shell to move to a different location, and then deposit up to 100 eggs into a wax chamber she creates for them. No males are known, reproduction is by parthenogenesis, and several egg-laying episodes may occur each year by a female. Within a few days the eggs hatch and the mobile crawlers emerge from their chamber and move to nearby roots to feed. As they molt these nymphs then create their own wax chamber, and it is these visible whitish yellow “pearls” that may be found when soil is removed. In the fall the fully developed adult scales then overwinter within their pearl. These scales infest primarily grasses, but have also been found feeding on roots of grapes.

Identification:
Found as either the pink adult females or the yellowish round pearls within the soil. Close examination will reveal legs or mouthparts present. Damage to turf shows as yellowing patches expanding slowly outward, with turf ultimately turning brown and dying.

Characteristics Important to Control:
The very slow spread of the scales, at no more than about 6 inches per year, limits the damage they may cause. Infestations in new locations may be the result of movement of soil or contaminated equipment that has the soil and scales on it. Insecticides do not appear to be effective on this scale due to its subterranean existence and the wax scale that surrounds it. Good turf health will be preventive, along with possible physical removal of the turf and soil that harbor the insects.