Bronze citrus bugs

What are they?

Bronze citrus bug is a native insect that feeds on most varieties of citrus trees in QLD and NSW. They are large shield-shaped insects about 25mm long and are bronze to nearly black in colour. They change in colour and appearance throughout their lifecycle, from small bright green eggs to fourth stage nymphs being bright orange initially, then changing to green/grey in colour later.

Adult bugs can spray a well-aimed pungent and caustic defensive liquid when threatened, earning them the name of ‘stink bugs’. These sap-sucking pests can become a serious problem on poorly maintained citrus trees. Bugs will suck the sap from young shoots, and from fruit and flower stalks, causing shoots to wilt and flowers and fruit to drop.

How do you manage them?

• Regular monitoring, along with prevention and control will stop a major infestation.

• Look for clusters of eggs or second stage nymphs on the underside of leaves.

• Look for later stage nymphs and adults on shoots and young fruit. If discovered, pick them off by hand and drown them in a bucket of soapy water.

• Being mindful to wear gloves and eye protection when handling then to avoid their defensive fluid.

Tiny wasps parasitise bug eggs and assassin bugs and robber flies are natural predators. Planting a variety of herbs and flowers near your citrus will encourage these natural enemies.