Italian Xylella outbreak sparks fresh warning for Aussie olive growers

Image: An olive grove decimated by Xylella. (Rodrigo Krugner, USDA)

By Laura Thomas

A Xylella outbreak in southern Italy has sparked a fresh warning for Australian olive growers, as efforts to keep the country disease-free continue. 

Xylella fastidiosa has been detected in an olive tree in Minervino Murge, near Bari, in an area previously believed free of the devastating bacteria.

According to reports, ongoing monitoring operations across the wider Apulia region allowed local researchers to identify early infection, described as a ​“point-source outbreak”. 

But the development has highlighted a new source of concern. Existing controls have not been enough to stop the spread, sparking calls for increased protection measures for Italy’s most important olive-producing area.

Back at home, Xylella is considered Australia’s single highest pest threat, due to its potential to cause significant disease to a wide variety of plants including native and cropping varieties, such as olive trees.

An outbreak on home soil would be impossible to eradicate and devastate the agricultural sector, leading to significant economic loss and environmental damage.

Australian olive growers have remained on high alert since Xylella’s spread was confirmed in China early this year.

Emergency measures were implemented by the Department of Agriculture, Fisheries and Forestry to manage the risk of the bacteria entering Australia via imported host plants and some seed species.

This included strict screening, treatment and certification measures for plant nursery stock imported from China, as well as revisions to some trade permits.

The outbreak also prompted action from the Australian Olive Association, via review of its Biosecurity Plan for the Olive Industry. 

This document informs the government and other industries about the most critical pests and diseases threatening the olive industry and forms part of Australia’s broader biosecurity strategy. 

It outlines the current measures in place to minimise infection risk and actions to be undertaken in the event of an incursion.

Australian Olive Association Chief Executive Officer Michael Southan said while Australian remained Xylella free, all producers had a role to play in national biosecurity.

“With olive harvest continuing and high levels of movement in and out of groves across the country, we are urging olive growers to stay vigilant,” he said.

“This latest outbreak in Italy shows that we can never afford to become complacent about biosecurity.

“Despite all the controls in place within the Apulia region and their ongoing experience managing this pest, it hasn’t been enough to stop the spread.”

Mr Southan said ongoing international trade in plants and other products created an ongoing biosecurity risk for Australia.

“Due to this constant movement across our border and despite our best efforts, the risk of new pest and diseases remains a threat,” he said.

“This is why it’s so important to be well educated and have the right procedures in place on the ground to manage a potential outbreak if and when it happens.”

On-farm biosecurity best practice is key in maintaining Australia’s reputation as a producer of quality food and fibre.

For more information on how you can play your part, check out the AOA’s biosecurity best practice checklist below, or visit www.australianolives.com.au/biosecurity-plan-for-the-olive-industry/ .

Biosecurity Best Practice Checklist

• Manage biosecurity risks – prepare an on-farm biosecurity plan
• Plant disease resistant varieties and avoid planting in infected soils
• Know your high priority biosecurity pests – induct your employees
• Monitor your grove – report anything unusual to the exotic pest hotline
• Implement good grove hygiene – keep it clean, removal or composting of pruning wood, disinfection of pruning tools
• Enforce visitor movement requirements – people and vehicles
• Use grove biosecurity signage
• Provide vehicle and fruit bin wash down facilities – arrive clean / leave clean

Sources: www.oliveoiltimes.com.au; www.agriculture.gov.au; www.australianolives.com.au