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The Department of Agriculture and Food, Western Australia (DAFWA) is continuing its surveillance and
management of the tomato-potato psyllid. The psyllid can vector Candidatus Liberibacter solanacearum,
a bacterium that causes zebra chip in potatoes. In this edition of Potatoes Australia, DAFWA answers the
most frequently asked questions about zebra chip disease.
TOMATO- POTAT O PSYLLID AND ZEBRA CHIP:
WHAT POTATO GROWERS NEED TO KNOW
As of 16 May 2017, the Department of Agriculture and Food,
Western Australia (DAFWA) has put its surveillance and
diagnostic resources focus in the metropolitan Control Zone
to further increase confidence levels that Candidatus
Liberibacter solanacearum (CLso) in tomato-potato psyllid
(TPP) is not present in Western Australia.
The determination that TPP is not technically feasible to
eradicate was endorsed at a National Management Group (NMG)
meeting held in April (turn to page 18 for more information).
A Quarantine Area Notice currently remains in place to direct
the movement and treatment of specified commercially-
produced fruit, vegetables and seedlings to contain and control
the pest. It divides Western Australia into three quarantine
zones – a Control (red) Zone, Suppression (orange) Zone
and Watch (blue) Zone. More information can be found at
In the meantime, DAFWA has provided answers to commonly
asked questions about zebra chip disease.
CLSO AND ZEBRA CHIP DISEASE – WHAT IS IT?
CLso is a bacterium that causes zebra chip disease in potatoes
and can be carried by TPP.
The disease causes infected potatoes to develop visible dark
stripes after frying. While not harmful to human health, zebra chip
disease causes quality issues which renders potatoes not suitable
for commercial sale.
Infected tubers may also fail to produce plants.
TPP was detected for the first time in Australia earlier this year.
At this time, the psyllid has only been found in Western Australia.
To date there has been no detection of CLso in TPP or host
plants within Western Australia.
WE HAVE FOUND THE PSYLLID, WILL AUSTRALIAN
POTATOES EVENTUALLY GET THE DISEASE?
Not necessarily. Canada has had the pest for decades without
testing positive to the CLso bacterium.
As part of the national response to the detection of TPP, DAFWA
has set thousands of sticky traps on commercial and residential
properties throughout the state within host crops, including
tomato, potato, sweetpotato, capsicum, chilli, eggplant, goji berry
and tamarillo. These traps provide surveillance data as well as
collecting insects for CLso testing.
DAFWA has tested 1,000 psyllids as well as 6.6 tonnes of
potatoes (over 32,000 tubers) with no positive detections of CLso.
HOW DO YOU TEST FOR CLSO?
The first step in CLso testing is to conduct a fry test, where
potato samples are fried and inspected for signs of the bacteria,
which presents as dark bands or stripes.
Suspect samples are retested and if required, a polymerase
chain reaction (PCR) test – a DNA test – is conducted in the
South Perth lab. Of the 32,000 tubers tested, 794 have
undergone PCR testing as part of the TPP incident response.
HOW SHOULD I REPORT SUSPECTED SIGNS OF TPP
OR ZEBRA CHIP?
Commercial potato growers, particularly in regional
areas of Western Australia, should continue to check for
signs of TPP. Report any suspect signs of the pest to DAFWA
through the MyPestGuide Reporter app or to your state’s
biosecurity department.
Alternatively, growers who suspect that TPP may be present
in their crop need to report this to their state or territory
department of agriculture or primary industries by phoning
the Exotic Plant Pest Hotline on 1800 084 881.
Agriculture Victoria is reminding potato growers to be aware
of signs of tomato-potato psyllid (TPP) and regularly check
their crops.
There have been no detections of TPP in Victoria to date.
TPP was first detected in Western Australia in February 2017
and Agriculture Victoria has imposed strict restrictions on the
importation of any risk material from Western Australia as a
precautionary measure to prevent the pest from entering Victoria.
Agriculture Victoria began a state-wide surveillance program
in May 2017 in an effort to confirm Victoria remains free of the
exotic pest. Agriculture Victoria is using best practice diagnostic
protocols through its state accredited laboratory AgriBio at La
Trobe University to test the plant samples.
Confirming Victoria’s Area Freedom of TPP is of the
utmost importance and will ensure growers are able to
continue to trade.
Agriculture Victoria appreciates the support of industry as
it conducts the surveillance program.
A fact sheet is available for growers to help identify the signs
of TPP on solanaceae, convolvulaceae and brassica plants.
Growers and community members are reminded that it is an
offence under the Plant Biosecurity Act 2010 not to report a
suspect TPP outbreak. This can be done by calling the Exotic
Plant Pest Hotline on 1800 084 881, Agriculture Victoria on
136 186 or by emailing .
For more information, please visit .
VICTORIAN GROWERS ASKED TO REMAIN VIGILANT
For more information, contact DAFWA on 08 9368 3333 or visit
This communication has been funded by Horticulture Innovation Australia
using the fresh potato research and development levy and funds from the
Australian Government.
Project Number: PT15007
INFO
R&D | INDUSTRY UPDATE |
Foliar symptoms of Candidatus Liberibacter solanacearum infection.
Image courtesy of Plant & Food Research New Zealand.
Adult tomato-potato psyllid. Image courtesy
of Plant & Food Research New Zealand.