Citrus powdery mildew
Have you seen citrus powdery mildew symptoms?
Be on the lookout for symptoms and report them to Biosecurity Queensland.
Early detection and reporting are the key elements in controlling the disease.
Call us on 13 25 23
Citrus powdery mildew is a fungal disease that causes leaf and shoot distortion, premature leaf and fruit drop, and twig and branch dieback. Severe infection can significantly reduce tree productivity, fruit quality and yield. The disease can also be a major problem in citrus nurseries. It has been reported to cause serious damage to mandarins, particularly nursery stock, in Asia.
Citrus powdery mildew is a plant disease and is not harmful to people or animals.
Citrus powdery mildew is caused by the fungi Oidium citri and O. tingitaninum. Powdery mildew on other crops, though similar looking, is caused by different species of powdery mildew fungi.
All citrus cultivars can be affected, though some cultivars appear more susceptible than others. In India, the citrus varieties that are most susceptible are mandarins, sweet oranges and tangerines.
|Spread of disease|
This disease produces tiny, powdery spores that can survive on fallen leaves. It can be transported long distances by wind, on people (clothing, hands), equipment (e.g. pruning tools, mechanical harvesters or hedgers) or vehicles. Movement of infected citrus planting material poses a significant threat.
The Australian Government's Department of Agriculture, Fisheries and Forestry closely regulates approved host plant imports and monitors for illegal plant movement.
|Management and quarantine|
There are simple steps you can take to protect your farm:
The disease is common in parts of Asia where it is prevalent in shady, poorly ventilated orchards. There have also been reports from Uganda, Israel, Central and South America and the United States (California). Citrus powdery mildew is not known to occur in Australia.
|Reference and acknowledgement|
Sandra Hardy (NSW DPI), Paul Holford (University of Western Sydney) and Andrew Miles and Ceri Pearce (Biosecurity Queensland, Department of Agriculture and Fisheries).