Xylella and exotic vectors

Everyone needs to keep an eye out for symptoms of xylella and its insect vectors.

Xylella:

• Spreads by people moving infected plant propagative material, and transmission by insect vectors which spread the pathogen to other plants. It is not carried on, or spread by seeds.
• Grows within the xylem and clogs the water flow vessels of the plant causing the plant to dehydrate and eventually die.

Symptoms vary between hosts and can be easily confused with water stress or the presence of other pathogens.

Main symptoms are:

• scorching of leaves
• browning and loss of leaves
• stunting of young shoots
• gradual reduction in fruit size over time
• dieback and eventual death of the plant.

 

Some plants can be infected with xylella but not show any symptoms or significant effects.
Virtually all sucking insects that feed on a host plant’s xylem fluid are potential vectors of xylella, such as:

• sharpshooters
• spittlebugs
• related leafhoppers.

Significant vectors such as meadow spittlebug (Philaenus spumarius) and the glassy-winged sharpshooter (Homalodisca vitripennis), which are not in Australia, have aided the establishment and significantly increased the impact of xylella in other countries. Spittlebugs are usually less than 13 mm long but may be up to 27 mm; while sharpshooters and froghoppers range in size from 2-30 mm but average 13 mm.

 

Many sucking insects already present in Australia are expected to be vectors and be able to spread the pathogen should it be introduced to Australia.

Importers

If you work around imported plant material, including cut flowers, nursery stock, fruit and vegetables, you need to look for disease symptoms and insect vectors.

Growers and home gardeners

You should only get plant material from clean, accredited suppliers. Check your plants frequently for any new pests or unusual symptoms, and always use good hygiene and biosecurity practices to prevent the entry, establishment and spread of pests and diseases.

Find out more about farm biosecurity.

All Australians and international tourists have a role to keep out exotic pests and diseases. Xylella is present in a number of countries. Australia remains free of this exotic pest. We need your help to keep it this way.

Check what you can and cannot bring into Australia, whether you are a:

• importer
• online shopper
• traveller arriving in Australia.

Xylella is Australia’s number 1 most unwanted

There is no evidence of xylella being successfully eradicated once it has established. For this reason, preventing the entry of this pathogen into Australia is vital.

Import restrictions and biosecurity measures

Some items, by law, are subject to certain import conditions to be allowed into Australia. Please check the Biosecurity Import Condition System (BICON).

Be aware of any xylella biosecurity measures that may be in place for incoming goods and conveyances. Industry advice notices are reviewed regularly and could change.

Containment is critical. This could be as easy as bagging a suspect plant specimen that has symptoms or stopping an insect escaping by closing the doors on a shipping container.

Controlling vectors and removing infected plant material are the only control options, in conjunction with movement restrictions on infected plant material, to limit its spread. Identification and use of resistant plant stock may provide a long term management option, as the disease would be nearly impossible to eradicate.