Every rose has its thorn

These rose plants were smeared with potting mix and were covered in fungi and bacteria.

While there is a lot of attention on keeping African swine fever out of Australia, the number one nasty in the plant world is Xylella.

Xyella loves to hitch a ride across international borders on roses.

Live asparagales shrub plants and fig cuttings were also intercepted at Sydney earlier this year.

There is no cure for Xylella.

It is Australia's number one priority plant disease risk and is a threat to many industries, including cherries, citrus, tree nuts, production nurseries, summer fruit, olives and viticulture.

Agriculture, Water and the Environment Department head of biosecurity Andrew Tongue said importing plants carried a huge risk of plant diseases.

"Roses are a host for Sudden oak death and Xylella fastidiosa, both of which could be absolutely devastating to Australia's horticulture and ornamental industry, and our native species and forestry, if they were to ever establish here," Mr Tongue said.

MORE READING: Australia's seawater moat is no guarantee of protection.

"Xylella has destroyed olive groves in Italy that are centuries old, and we know it infects hundreds of plant species in 98 plant families," he said.

" The economic costs of Xylella to Europe have been estimated in the billions of Euros. In Australia, the potential economic impact to the wine industry alone has been estimated at $2.8 and $7.9 billion over 50 years.

"It's a risk we take seriously. In June, Australia expanded our emergency response to the threat of Xylella to cover more plant species.

"Not only does it attack commercial varieties of plants, but it's also a serious threat to native plants and can cause disease in more than 500 different plant species."

NSW Farmers horticulture committee chairman Guy Gaeta said Xylella posed an incurable threat to more than 500 plant species and native plants.

"A single disease outbreak could cost billions and would be fatal to our pursuit of $30 billion in farmgate output by 2030," Mr Gaeta said.

More facts:

Due to a change in host range, emergency measures for Xylella were extended in June to nursery stock belonging to the following plant families:

If you are unsure about the biosecurity status of goods that you have brought into Australia or received in the mail, please report a biosecurity concern by calling 1800 798 636.

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