Ground Pearl

SCIENTIFIC NAME:

Margoroides spp.

ORDER:

Hemiptera

How to identify Ground Pearl:

Ground pearl can be identified by either their immature or mature forms:

• Immature ground pearl are a soft bodied insect with a pale and elongate body to 5mm long, possessing inconspicuous legs and antennae.

• As they mature the ground pearl develops into a pink, globular-bodied pest with a large, soft abdomen and small legs and mouth parts clustered towards the front of the body, up to 4mm long.

What is the lifecycle and biology of Ground Pearl?

Overwintering takes place in the ground pearl stage. Females usually reach maturity in late spring and emerge from their cysts. After a brief period of mobility, the wingless females settle 5 to 7.5 cm deep in the 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 favourable for emergence, female nymphs may remain in the ground pearl stage for several years.

The ground pearl nymphs extract juices from underground plant parts. The damage is most apparent during dry spells when irregularly shaped patches of grass turn yellow.

Turf affected by ground pearl in these patches eventually turns brown and dies. This often occurs in couch grass bowling greens, resulting in devastating damage and the loss of large areas of turf.

No insecticide is currently specifically registered for the control of ground pearl. Although insecticides such as Supracide, Maldison, Dimethoate and Bifenthrin have known efficacy.