What do they look like? Bronze orange bug give away their presence by their foul smell. The young pale green nymphs appear in winter, their colour changes through orange to bronze as they grow to adults. They can be serious pests in some areas, causing flower and fruit drop by sucking on the stalks. If your bugs are up to 2.5 cm long and are bronze to nearly black with a prominent black patch on their abdomen, they are Bronze Orange Bugs (Musgraveia sulciventris, Family Tessaratomidae).
These bugs lay pale green eggs in groups. The second stage nymphs may be found on the undersides of leaves during winter. The nymphs are much flatter than the adults and change colour from green through salmon, orange and pink. They can be in plaque numbers on citrus late spring - summer.
What do they do? Bronze Orange Bugs are found in temperate and tropical regions along the East Coast of Australia. The caustic fluid squirted by these bugs is very dangerous and painful, particularly to the eyes. Be wary of pets close by as the fluid can cause blindness when squirted in the eyes. They are a major pest to citrus and would have originally eaten native limes.
How are they controlled? If you spray your citrus trees regularly each fortnight with Pest oil or the Eco Oil from early spring, you will discourage (prevent but not control) both Bronze Orange Bug and Citrus Leaf Miner. Spray in the evening on both sides of the leaf. You can give your oil sprays a bit of extra bite by adding Pyrethrum which is a knockdown insecticide.
The natural predator of the strinkbug are assassin bugs and a few types of birds. Natural pesticides such as pyrethrum sprays are also effective. Always wear goggles as these bugs can squirt a smelly, acidic liquid into your eyes. Early control is essential. Control them before they reach their adult, breeding stage, and then you may not see them again until the following spring.
What can I spray? Chemical control with a low toxic insecticide - Confidor or Conquer to non-fruit bearing citrus.