NSW Department of Primary Industries

Xylella

More topics in this section

Xylella banner

Xylella is a bacterial disease that causes leaf scorch, yellowing and loss of leaves, stunted shoots, reduced fruit size, dieback and eventual death of plants.

Australia remains free of Xylella, however it is our number one National Priority Plant Pest (NPPP) as it can cause a devastating impact to Australian plant industries – including many of the crops we rely on for food and fibre. Establishment of the disease could have significant impact to our farming industries, our economy and the environment.

There is no cure for Xylella, which makes it even more critical to remain vigilant and prevent entry, establishment and spread of the disease.

How to spot Xylella

  • Look for scorching of leaves on plants that mimics water stress. Symptoms gradually spread through the tree or vine often from the canopy down
  • Keep an eye out for exotic plant pests, such as the meadow spittlebug and the glassy winged sharpshooter. Report anything suspicious to the Exotic Plant Pest Hotline on 1800 084 881

Notifiable statusgrapevine leaf showing symptoms of xylella

Xylella is a notifiable plant disease in NSW. If you see it, report it!

All notifiable plant pests and diseases must be reported within 1 working day.  You can report notifiable plant pests and diseases by one of the following methods:

A full list of notifiable plant pests and diseases can be found in Schedule 2 of the NSW Biosecurity Act 2015.

We all have a duty in keeping Xylella out of NSW. Here’s what you can do:

Gardeners:

  • Know where your plants and seeds come from – and don’t buy seeds from overseas.
  • Don’t plant foods brought from the supermarket as they carry a higher risk of disease.
  • Keep an eye out for symptoms in your garden. Xylella can appear in common backyard plants such as lavender, oleander and polygala - as well as fruit crops such as citrus and almonds.

Travellers:

  • Don’t bring plants or plant material back from overseas.
  • Check your luggage for any unwanted pests, seeds or plant material.

Farmers:

  • Routinely inspect your crop for Xylella symptoms
  • Regularly sweep net lower vegetation and ground covers around your crop to check for spittlebug and sharpshooter insects

Importers:

Infection and spread of Xylella

Xylella bacteria live within the xylem of the plant, which is responsible for transporting water and nutrients from the roots to the leaves. An infected plant will display signs of water stress, with a common symptom of scorching of the leaves.

Xylella can be spread between plants through grafting of infected plant material, or by insect vectors that feed on the plant. Common insect vectors include the meadow spittlebug and the glassy winged sharpshooter, neither of which are found in Australia. However, species of native insects are capable of transmitting the pathogen if Xylella is established in Australia.

Xylella affects a wide range of plants (currently 712 known host species). Given the variety of host plants, there are a number of naming conventions for Xylella including Pierce’s disease in grapevines, leaf scorch in almonds and oleander, phony peach disease in peach, pear leaf scorch in pears, leaf scald in plum, variegated chlorosis in citrus and olive quick decline in olives.

There are two key pathways via which Xylella could enter Australia.

  • importation of infected plants or planting material such as budwood, cuttings and rootstock
  • insects infected with the disease. Two exotic plant feeding insects, meadow spittlebug and the glassy winged sharpshooter, are also the subject of biosecurity measures to keep them out of Australia.

Insect vectors

All sucking insects that feed on xylem sap are potential vectors of Xylella.

Two insect vectors of major concern are Glassy-winged sharpshooter (Homalodisca vitripennis) and the meadow spittlebug (Philaenus spumarius).

Both these insects are exotic plant pests (NOT present) in Australia. There are also several native insects that could vector the disease if it were to arrive in Australia.

World distribution

Xylella has spread around the world with movement of asymptomatic plants. Mutations over time has increased the host rage of the pathogen and its impacts on agriculture globally. Infection has been confirmed in the Americas, Middle East, China, Japan and Europe. It has been causing significant issues for agriculture in Italy and Spain over the last 10 years. Periodic detections in France, Germany, Switzerland have been successfully eradicated when found early.

Control

There is no known cure for Xylella. Once a plant is infected it will carry the pathogen for life.

Prevention is the best option for the management of Xylella. Removal of infected plants and vector control programs are the primary control strategies being used overseas to reduce pest pressure and slow down the rate of spread.

More information

www.dpi.nsw.gov.au