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12 | February/March - 2017 | 13
R&D | RESEARCH UPDATE |
Common scab is a widespread issue that causes a blemish disease in potato tubers. While the incidence of
Common scab in Australia has declined in the past five years, the disease is still a problem in the country,
particularly for fresh market and seed producers. Potatoes Australia has produced this update to explain how
Common scab occurs and what growers can do to manage the disease.
MANAGING COMMON SCAB IN POTATOES
Common scab is a prevalent soil-borne disease that occurs in
potato growing regions throughout the world.
Caused by the bacteria-like organism Streptomyces scabies,
young rapidly growing tubers are attacked, which then develop
into unsightly corky scab lesions on the tuber surface. The scab
is roughly round but can join to form scabbed areas and can be
superficial, slightly raised or deep pitted, sometimes extending
several millimetres into the tuber.
Other parts of the plant are not affected and no visual symptoms
of infection in above-ground parts of the plant are obvious.
Incidence and severity can vary significantly depending upon
the season, variety and region. A range of conditions impact the
severity of the damage to the potato – affected tubers may show
either shallow or deep scabs, or a combination of both.
University of Tasmania Associate Professor in the School of Land
and Food Dr CalumWilson has, over the years, undertaken a number
of research projects with a focus on Common scab.
“These projects looked at a wide range of factors and attempted
to develop robust disease control strategies. We had projects looking
at the effect of irrigation, soil attributes, seed and soil chemical
treatments, the importance of clean seed tubers and carryover in
soil,” Dr Wilson said.
“In recent years we made some significant breakthroughs with the
selection of highly disease-resistant plants from commercial varieties
and the use of novel foliar and seed treatments to inhibit disease.”
DISEASE MANAGEMENT
Common scab is promoted by relatively dry soil conditions at tuber
set. Improvements in irrigation scheduling during this period by
potato growers has assisted in reducing disease incidence.
“Also, planting into more acidic soils will generally reduce disease
while neutral or more alkaline soils will increase disease. The
application of lime prior to potato planting will certainly exacerbate
the disease, so try to avoid liming if at all possible.”
Seed certification and seed treatments are important, according
to Dr Wilson.
“It’s pretty obvious that seed-borne contamination is an important
source of inoculum for the disease, so making sure you plant
certified seed and use appropriate seed treatments where available
certainly helps.”
FURTHER ADVICE
Growers are also advised to use less susceptible varieties (if possible)
and treat most root crops such as carrots, swedes, beets, radish and
parsnip the same as potatoes when planning rotations, as they can
also host the disease. The pathogen will survive for long periods
in the soil but prior cropping with susceptible plants will increase
pathogen levels and subsequent disease risk.
Crop uniformity is recommended – a rapid and even emergence
is an important means of reducing the impact of the disease in
potato growing areas.
“Another thing that was discovered by the local industry here in
Tasmania is that the timing of planting seems to have an effect,” Dr
Wilson said.
“The later growers planted the crop, the less Common scab
disease they were seeing. No one has actually really tried to dissect
that to work out why that’s the case – it may well be that you have
a much tighter window when infection occurs and that disease is
better controlled in that window.
“You can end up with slight yield penalties with planting later, but
you seem to get less disease. This effect may be a localised factor for
Tasmania or it may be more widespread; more work is needed to see.”
For more information, please contact Dr Calum Wilson at calum.wilson@
. The topic for this article was selected following the results of
PT13013 A review of knowledge gaps and compilation of R&D outputs from
the Australian Potato Research Program.
This communication was funded by Horticulture Innovation Australia Limited
using the Fresh Potato Levy and funds from the Australian Government.
Project Number: PT15007
INFO
Common scab. Image courtesy of Florida Division of Plant Industry, Florida
Department of Agriculture and Consumer Services, .
Horticulture Innovation Australia (Hort Innovation),
using the National Potato Levy and contributions from
the Australian Government, invests in a wide-range of
R&D projects that aim to improve the future viability of
the potato industry and its growers. Potatoes Australia
spoke to Hort Innovation Relationship Manager
Christian Patterson about his role in supporting potato
growers, finding out what their long-term needs are
and how they can be achieved.
COLLABORAT ING WI TH
POTATO GROWERS TO
DEL IVER LONG-TERM,
SUSTAINABLE RESULTS
Christian Patterson regularly travels around Australia to different
potato growing regions in a role that is vital to the long-term
success and viability of the country’s potato industry.
As a Relationship Manager at Horticulture Innovation Australia (Hort
Innovation), Christian’s role is to ensure that the nation’s growers
are aware of developments in both the fresh and processed potato
industries, as well as the sweetpotato industry and the Consumer
Alignment strategic investment pillar of the vegetable industry.
Christian entered the horticulture industry more than eight years
ago, joining Woolworths in its Primary Freight Division. He then
moved into the role of Category Manager with Perfection Fresh
and Fresh Produce Group before accepting the role of Relationship
Manager at Hort Innovation 16 months ago.
A PRIMARY FOCUS
Currently, Christian is working closely with the fresh and processed
potato industry Strategic Investment Advisory Panels (SIAPs) to
develop the next potato Strategic Investment Plan, which aims to
accurately reflect the industry’s R&D funding priorities over the
next five years.
“The involvement of these panels is critical to the success of the
funding of various projects, as they are the voice of the greater
industry and represent a cross-section of industry experts –
growers, suppliers and the like,” Christian said.
“That’s allowing us a varied, experienced group to form views and
offer advice as to what areas of investment are most important and
critical to their respective industry.”
GROWER INVOLVEMENT
One valuable aspect of Christian’s role as Relationship Manager is
the ability to visit Australia’s potato growers, who are spread out
across the nation.
“My best work as a Relationship Manager is done face-to-face with
the growers, and the relationships between those who I do manage
to go and see are very strong and robust,” he said.
“I like to take a personal involvement with as many potato growers
as possible outside of the SIAPs. These vary from something as
simple as a phone call to a road trip, ensuring that I’m touching base
at the ground level with our levy-payers. Sometimes the best advice
and industry information is gathered when you’re standing in the
field with a grower and understanding the issues at their level.”
He added that Hort Innovation plays a significant role in the
adoption of R&D on-farm in the potato industry.
“As the body that invests the levies collected, we’re responsible
(along with the SIAPs) to ensure we’re protecting industry, building
strong succession plans and supporting industry in its growth and
delivering results along the way,” he explained.
“Whether it be from a seed grower to an end-product grower,
these are all important spokes in the wheel. The adoption of the
R&D that is developed is also very important and has been made
possible in conjunction with industry, the SIAPs and Hort Innovation
to benefit the industry.”
FURTHER GROWTH
Christian believes there is great potential for growth in the
Australian potato industry, with exporting on the radar for many in
the industry. Providing support for younger potato growers
is also a priority.
“Personally, I think the biggest opportunity for growth is in exports,
as long as we can ensure all the checks and balances that are
required are in place,” Christian said.
“I also see an opportunity with the younger growers forging their
way into the industry. Supporting these younger growers along the
way is vital – there’s a lot to learn from these guys and they also
need our support from the ground up.”
Australia’s potato growers are able to contact Christian should
they require assistance, or need advice on any industry issues. They
are also encouraged to become members of Hort Innovation to be
updated with regular advancements in R&D.
“I want potato growers to be able to contact me at any time and
be safe in the knowledge that they are being heard and that I am also
actioning their requests in a timely manner. That is my ultimate goal.”
For more information, please visit or contact Hort
Innovation Relationship Manager Christian Patterson on 02 8295 2382
or 0433 896 753 or email
This communication has been funded by Horticulture Innovation Australia
Limited using the Fresh Potato Levy and funds from the Australian Government.
Project Number: PT15007
INFO
R&D | INDUSTRY INVESTMENT |
Hort Innovation Relationship Manager Christian Patterson.