Ground pearls (Hemiptera: Margarodidae) in crops and pastures: biology and options for management.

Ground pearls (Hemiptera: Margarodidae), so called for their shiny spherical cyst stage, are important root-feeding pests of a broad range of plants predominantly belonging to the family Poaceae. In the tropical and subtropical regions of eastern Australia, ground pearl species cause significant damage on sugarcane and turf grasses and have been identified at multiple sites of pasture dieback in Queensland. The potential impact of ground pearls on pasture production in Australia and elsewhere is largely unknown. This paper reviews Australian and international literature on the biology and management of this poorly understood group of pests. Ground pearls have several features that make control difficult, including a resilient cyst which provides resistance to drought and excessive moisture, a relative impermeability to insecticides, and ease of dispersal through movement of soil. Ground pearls can also modulate the period of encystment to survive adverse environmental conditions, with some species capable of surviving for years while disassociated from a host. No insecticide effectively controls ground pearl cysts. Biological control agents have been identified for some species; however, these pathogens are relatively ineffective on subterranean ground pearl cysts. Cultural control methods such as cultivation and fallowing have helped to reduce ground pearl populations in sugarcane. In turf, practices that maintain plant health such as adequate irrigation and nutrition can mask signs of ground pearl infestation. The paucity of research conducted on the biology and impact of ground pearls represents a constraint to improving management of this pest. Ground pearls are important pests of a broad range of plants predominantly belonging to the grass family (Poaceae). In eastern Australia, they cause significant damage on sugarcane and turf grasses, and have recently been found in pasture situations in Queensland, but their impacts are unknown. This work reviews Australian and international literature on the biology and management of ground pearls, finding that relatively little research has been undertaken and several knowledge gaps remain. [ABSTRACT FROM AUTHOR]