Macadamia lace bug

Ulonemia concave

Macadamia Lace bug (Ulonemia concave) is a small insect, with adult lace bugs being up to 3-4mm in length (figure 1). These insects are sap suckers. They suck the sap from flower buds, which causes the flowers to desiccate. This insect has the ability to cause crop failure in orchards if it is not managed.

The life cycle of Macadamia lace bug has not been studied in detail, but it is estimated that it is between 12-18 days. Lace bugs have been found to survive at temperatures as low as 5°C, giving them the ability to over winter in cold locations.

The eggs of lace bug are laid in the florets of flowers. These eggs hatch and the nymphs (figure 2) move up and down a flower raceme, feeding on developing flowers. These nymphs are yellowish to brown in colour. As the nymphs progress through their lifecycle stages they shed skins that are attached to flowers. These skins can be found on desiccated flowers that they have fed on, which indicates the cause of the racemes death.