PESTS
PHOTOS: GARY BEEHAG
PESTS
Pink ground pearl has for many years been a nemesis for Australian turf managers, particularly along the Eastern Seaboard. Gary Beehag provides some background on this mysterious pest, while superintendents write about their experiences and attempts to lessen its impact on their surfaces.
Above: The combination of a subterranean lifestyle and the insect’s waxy outer covering partly explains why the pink ground pearl is so problematic for turf managers 20
Going to
ground
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everal species of scale insects commonly known as earth or ground pearls occur in the warmer regions of coastal, mainland Australia and elsewhere. The pink ground pearl (Eumargarodes laingi) is arguably number one turfgrass insect pest wherever it occurs. Once established in turfgrass swards, populations of this insect pest inevitably remain problematic. The combination of a subterranean lifestyle and the insect’s waxy outer covering, partly explains why the ground pearl is so problematic for those grounds curators, bowling greenkeepers and golf superintendents unfortunate enough to have had first-hand experience in attempting to manage this pest.
DETECTION AND DAMAGE The ground pearl is a true bug (order Hemiptera) that largely has a subterranean lifestyle rendering it difficult to detect let alone manage. Official entomological records of the occurrence of ground pearl in Australia are limited to coastal regions of Queensland and New South Wales. However, the pest’s true distribution range in Australia is unknown.
AUSTRALIAN TURFGRASS MANAGEMENT 20.3
Ground pearl was reported as a troublesome insect pest of turfgrass in Australia from as early as the 1970s. I observed the presence of ground pearls on Tifdwarf couchgrass bowling greens way back in 1988 in the Northern Territory. Ground pearl populations and damage has been observed on bowling greens, golf course fairways and sportsgrounds. The only way to confirm the presence of ground pearl populations is by monitoring and careful observation. When locally abundant, pink ground pearl populations may be detected by very careful separation of the soil media from turfgrass root material, looking for the insect’s tell-tale, lifeform stage known as a cyst. If found, the cyst of the ground pearl is circularshaped, up to 4mm in diameter and pink-coloured; hence the name. The coating of the cyst is waxbased and highly water-repellent. Careful squeezing of ground pearl cysts between the fingers reveals the small-sized insect inside. Conventional flushing techniques using liquid detergents and other water-soluble products have proved unsuccessful to lodge this insect beneath turfgrass swards. Studies have indicated that ground pearls are capable of moving vertically through soils to lay their eggs up to depths of approximately 25cm, under ideal conditions. Monitoring and actual sighting of ground pearls is best achieved over the summer period during bright and hot sunny days. Many years ago one Sydney bowling greenkeeper even observed ground pearls on the green’s plinths one extremely dry and hot day in summer!