Diseases of plants: Citrus greening disease
Citrus greening disease is also known as Huanglongbing.
One of the worst problems in citrus trees is citrus greening - a bacterial disease that has no cure. It grows in the tissue of citrus plants and eventually causes the tree to die. It is spread by a sap-sucking insect that is not present in Australia. Bringing infected material into Australia could introduce the disease and the insect that spreads it.
Keep a Top Watch
Keep a watch for sick citrus trees in your area or throughout your travels. A yellowing that spreads slowly over the tree or through an orchard is a sign of the disease. Look out for people smuggling citrus planting material into Australia. If in doubt, contact your Quarantine officer.
Profile: The disease makes the tree canopy turn yellow until the tree eventually dies. The only way to stop the disease is to destroy all infected trees and replace them.
Identification: It can be hard to recognise citrus greening because it can look like the tree has a lack of nutrients. Infected trees turn yellow, with blotchy, mottled leaves and small, uneven fruit.
Photos below: The tree canopy turns yellow and eventually dies if affected by Citrus greening disease. Infected trees have mottled leaves. The only way to stop the disease is to replace infected trees.
Distribution: This disease is prevalent in southeast Asia and recently moved as close to Australia as northern Irian Jaya in Indonesia. People illegally moving citrus trees into Australia from these areas (including planting and grafting material) could bring in both the disease and the insect that spreads it.
Threat: The only way to rid citrus orchards of the disease is to replace infected trees, so the cost of an outbreak to Australia’s citrus industry would be enormous. Commercial plantations would suffer most severely, with income and job losses.
Quarantine: Quarantine is the best way to stop citrus greening from entering Australia. The biggest threat is people smuggling infected planting material into the country. AQIS is working with the citrus industry to encourage early reporting of any citrus diseases.