Xylella fastidiosa

Xylella fastidiosa has been named the number one unwanted plant pest for Australia in 2016 and is a High Priority Pest for the wine industry.

“It’s a major threat due to multiple hosts and vectors, rapid impact and global spread, and we need to keep it out,” says Inca Pearce, Vinehealth Australia CEO.

Xylella fastidiosa is an invasive bacterial plant pathogen which affects the xylem of plants where it blocks the movement of water, dehydrating the plant and causing death within a couple of years. While it’s known as Pierce’s Disease in grapevines, it’s known by other names in other host plants.

Some plants can be infected with xylella but not show any symptoms or significant effects.

It is transmitted by sap sucking insects (in particular the glassy-winged sharpshooter in California) and by the movement of grapevine propagation material.

Xylella fastidiosa is currently found in Europe, Asia, Middle East, North America, Central America and South America.

“There are no treatments currently available to cure diseased plants in the field,” says Inca. “And the disease causes significant environmental and economic impacts across more than 350 commercial and ornamental plant species, including grapevines.”

Symptoms: Scorched leaves, browning and loss of leaves, stunted shoots, reduced fruit size over time, dieback, death of plant

What’s being done?

The Australian Government Department of Agriculture and Water Resources has initiated several activities to build capability including:

  • Conducting a pest risk assessment.
  • Evaluating import measures for vectors.
  • Preparing an economic assessment of potential impact.
  • Field visits to countries dealing with xylella including Italy and the United States.
  • Planning a regional symposium with international experts to share their experiences and knowledge.
  • Prioritising xylella as a surveillance target for the 2016-17 national plant health surveillance program.

“Emergency measures have been put in place in Australia including strengthened quarantine conditions for importation of nursery stock to prevent entry, based around the more than 100 plant hosts that are currently imported into Australia,” Inca says.

“And reporting systems are in place to report any detections.”

What can you do?

  • Be aware of the issue and monitor your crops.
  • Verify any suspicious symptoms.
  • Source plant material from high health schemes.
  • Support research into appropriate control and management strategies.

Vinehealth will continue to provide regular updates. For more information, visit the following links:

 
Pierce’s Disease

Pierce’s Disease, a key exotic disease to Australian viticulture caused by the bacterium Xylella fastidiosa, vectored by the Glassy-winged sharpshooter, was identified through the development of the Viticulture Industry Biosecurity Plan (IBP) where pest ratings considered the entry, establishment and spread probabilities for each pest in Australia, the likely impacts of the pest on cost of production, productivity, removal of quarantine barriers and market access, and how difficult the organism would be to control and/or eradicate.

The factsheet above from Plant Health Australia has been sourced from the Biosecurity Manual for the Viticulture Industry Version 1.0, produced by Plant Health Australia with support by Wine Australia, Australian Vignerons, Australian Table Grape Association and Dried Fruits Australia.

Featured photo courtesy Jack Kelly Clark