Communication of management

strategies for potato virus diseases in

Western Australian potato crops

Stewart Learmonth Agriculture Western

Australia

Project Number: PT00034

PT00034 This report is published by Horticulture Australia Ltd to pass on information concerning horticultural research and development undertaken for the potato industry. The research contained in this report was funded by Horticulture Australia Ltd with the financial support of the Potato Growing Industry Trust Fund. All expressions of opinion are not to be regarded as expressing the opinion of Horticulture Australia Ltd or any authority of the Australian Government. The Company and the Australian Government accept no responsibility for any of the opinions or the accuracy of the information contained in this report and readers should rely upon their own enquiries in making decisions concerning their own interests. ISBN 0 7341 0682 3 Published and distributed by: Horticultural Australia Ltd Level 1 50 Carrington Street Sydney NSW 2000 Telephone: (02) 8295 2300 Fax: (02) 8295 2399 E-Mail: horticulture@horticulture.com.au © Copyright 2003

PT00034 (30 June 2001)

Communicating the strategies to management of potato virus diseases for

Western Australian potato crops

Stewart Learmonth

Department of Agriculture, Western Australia

PT00034

Stewart Learmonth, Roger Jones, Mark Holland and Robert Money Department of Agriculture, WA Locked Bag 7 Manjimup WA 6258 Tel (08) 9777000 Fax (08) 97770001 EMAIL slearmonth@agric.wa.gov.au

Purpose of the report:

The aim of this project was to produce a video on managing potato leafroll virus and tomato spotted wilt virus in potato crops, that would provide WA growers with information to implement changes in the way they manage potato crops to reduce the risk of virus introduction and spread. The video was also produced with a view to making it applicable to potato growers in other states of Australia. The viruses discussed were potato leafroll and tomato spotted wilt.

The purpose of this report is to describe the work required to produce a video and lessons learnt that could be of value for the production of further videos aimed at technology transfer to farmers.

Funding

Funds to undertake this project came from the Department of Agriculture, Western Australia, the Western Australian Potato Producers’ Committee via the Western Australian Agricultural Produce Commission and Horticulture Australia Limited to and are gratefully acknowledged.

23 June 2003

Disclaimer

Any recommendations contained in this publication do not necessarily represent current Horticulture Australia policy. No person should act on the basis of the contents of this publication, whether as to matters of fact or opinion or other content, without first obtaining specific, independent professional advice in respect of the matters set out in this publication.

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CONTENTS

Video case cover sleeve 2

Media summary 3

Technical summary 3

Introduction 3

Materials and methods 6

Results 7

Discussion 8

Technology Transfer 9

Recommendations 9

Bibliography 9

Acknowledgments 9

Appendix 11

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VIDEO CASE COVER SLEEVE (colour page)

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Media summary

A video which shows potato farmers how to minimise virus levels in their crops was produced. The video contains much information that was previously only available in specialist textbooks. The improved format and the up-to-date content means that growers will have improved capacity to reduce virus diseases. This means that quality of seed potato crops as well as commercial crops will improve. Beneficiaries will be the consumer, processing factories, seed potato purchasers and seed potato growers. The video was produced in WA and will be distributed to all growers there.

It is recommended that the video be distributed to growers in other states as many of the principles are applicable to all potato growing regions of Australia.

Technical summary

Increased levels of tomato spotted wilt virus as well as low, but undesirable, levels of leafroll virus were concerning WA potato growers.

The problem was assessed to be one of technology transfer because management strategies were well known to pathologists. To manage these diseases growers needed more freely available, user-friendly information.

To achieve this, specialists from the Department of Agriculture, Western Australia, with the assistance of specialists in other states collated current, practical management strategies. These were presented in a video which will be distributed to all potato growers in WA.

The outcome will be that growers will be aware of current management practices involved with minimising the introduction and spread of the two major insect transmitted potato viruses.

It is recommended that the benefit of the project be assessed by determining the extent to which seed and commercial growers in WA implement appropriate strategies to assist them in producing crops of minimal virus levels. All contributors to this project should provide funding for this assessment. A quantitative assessment of virus levels could be obtained if AGWEST Plant laboratories continue with virus surveys of seed potato crops.

The video was produced in digital format, so as new important methods of managing viruses in potato crops are discovered, these can be incorporated into a revised version.

Introduction

Historical background

The insect transmitted potato viruses, potato leafroll and tomato spotted wilt, occur in Western Australia. Therefore potato crops may be infected with these viruses. In the past both viruses have been problems for individual growers, with the potential for industry wide problems. The presence of both viruses, all be it at low levels, has been confirmed by

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surveys of seed potato crops in WA (Mark Holland, AGWEST Plant Laboratories, pers. comm., 2002).

Seed and commercial potato growers in WA have implemented a range of strategies for protecting potato crops from leafroll virus infection. For seed growers, these included both calendar spraying and also, crop monitoring to base decisions on whether to apply insecticide. For commercial growers, there was a tendency to either ignore aphids or, at the other extreme, to spray at first sign of aphid presence.

Tomato spotted wilt virus has been an important disease in parts of eastern Australia, but has been at very low levels in WA. Therefore, growers in WA in general would have only rudimentary knowledge of those aspects of this disease that would enable them to recognise its presence and understand its sources and how it is spread.

Among growers there was also a range of competencies in recognising both pest and beneficial insects in relation to both virus diseases. Also, few growers would have had the confidence to undertake a monitoring program as a management tool for protecting crops from the introduction and spread of viruses.

Previously, the potato growers of WA sponsored the production of a video on monitoring aphids – the vector of potato leafroll virus (Berlandier, 2000). While this video was successful in this objective, growers requested a further video be produced that incorporated the role of aphids as vectors of virus, and also requested that the same information be included in the other insect transmitted disease – tomato spotted wilt virus. An impetus for this latter request was the severe outbreaks of this disease in the south-east of South Australia in the late 1990’s.

Why project was undertaken

The production of the video was requested by WA potato growers as a follow-up to a previously produced video on aphid monitoring. This project was undertaken to provide WA potato growers with up to date information in a user friendly format in order to clarify the steps they can take to minimise the levels of the two insect transmitted viruses, potato leafroll and tomato spotted wilt, in their crops.

Although WA growers requested the project, the video was produced with a view to it being relevant to all Australian potato growers.

Significance for industry

The two insect transmitted viruses that are the subject of this video can reduce the yield and quality of tubers (Stevenson et al 2001). Yield is reduced because infected plants have reduced plant vigour or stems are killed, while quality is reduced by discolouration of the flesh. In WA, the quality of seed potatoes is judged also by the level of virus infection, and limits exist under certified seed potato scheme rules (Anon 2001). It is important that seed potato crops have no or minimal virus levels because these diseases can be introduced to the larger areas of commercial potato crops through infected seed.

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Problems with virus infection of seed potato crops in WA in the past require that growers remain up to date regarding management practices they can implement to achieve crops of high quality with minimal virus levels. For potato growers producing commercial crops, an understanding of how viruses can be introduced and spread would give them a better understanding of relevant management practices that allow them to produce quality, high yielding crops.

Aims

The aim of this project was to produce a video on managing potato leafroll virus and tomato spotted wilt virus in potato crops, that would provide WA growers with information to implement changes in the way they manage potato crops to reduce the risk of virus introduction and spread.

The video was to be produced with a view to making it applicable to potato growers in other states of Australia.

Implications & impacts

With growers implementing the principles of virus management as depicted in the video, virus levels in potato crops would be reduced. This would be evident in surveys conducted on seed potato crops, and also reduced levels of virus observed by seed potato growers and reported by seed potato crop inspectors. Such a situation has advantages in building this sector of the industry’s reputation both for local and export markets for seed potatoes.

Potato production in Western Australia has been under some turmoil over the last decade. The closure of the Simplot processing potato factory in the 1990’s saw the loss of 30,000 tonnes of production in the south-west region. Since that time, although domestic consumption of fresh potatoes has increased slightly, there has been some dramatic increases in the volume of export potatoes (see Fig. 1). This has been largely through increases in export of fresh potatoes, mainly the crisping variety Atlantic. With this there has been some moderate increase in export of seed potatoes. Recently, the interest in export seed potatoes from WA to south east Asia has received a boost in potential. This has been driven by individual growers, as well as collaborative development project between Western Potatoes, the Department of Agriculture Western Australia and several Asian countries.

The situation of increasing exports of potatoes is occurring nationally as well – especially for seed potatoes (see Fig. 1). Likewise, the implementation of strategies that assist the production of export potatoes with minimal virus levels will help all Australian producers.

To help with this export development will be the development of a reputation for quality potatoes. The management of viruses in seed and commercial crops will be an integral part of this. The distribution of this video is part of this initiative.

As well as the implications for the export sector of potato production, this situation of a assured minimal or reduced virus levels in seed crops would be translated to increased confidence in commercial potato growers to reduce insecticide use against virus vectors. This would be based on both increased confidence in purchasing seed of minimal virus

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levels and an understanding of vector management based on monitoring and reduced importance of vectors in such crops. Growers of commercial crops would produce crops reaching their yield potential and of good quality where viruses have not been a limiting factor.

Fig. 1. The level of production of export seed, fresh and total potatoes from Australia and Western Australia over the period 1996/97 to 2001/02.

Materials and methods

Specialists in the Department of Agriculture produced a draft script for the video.

This was sent to three video producers for the purpose of obtaining quotes to have the work undertaken. Channel 9, Perth submitted the lowest quote and was awarded the job.

0

5000

10000

15000

20000

25000

30000

35000

40000

1996/97 1997/98 1998/99 1999/2000 2000/01 2001/02

Year

Tonnes

Australia - Seed WA - Seed Australia - Fresh WA - FreshAustralia - Total WA - Total

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Vision for the video was obtained from a number of locations in Western Australia including potato farms, Department of Agriculture laboratories, potato retailers and a wharf in Fremantle. Still vision was obtained from a number of sources (see Acknowledgments). The video was produced in digital BETACAM format.

The script for the video was edited for technical content and grammatical correctness by a number of people across Australia (see Acknowledgments and Appendix 1). The script was narrated on compact disk, which allowed it to be combined with the digitally recorded vision.

Specialists within the Department of Agriculture and a group of potato growers checked the first draft of the video. The representatives of the WA potato growing zones were asked whether they considers growers would prefer the material being available as a compact disk or VHS video.

The final version of the video was collated by staff of Channel 9, in concert with the senior author.

Results

The survey of WA potato growers was unanimous in their preference that the material be available as a VHS video. The main reasoning was that most growers would have a video player and, while computers are becoming more widely used by growers, video cassette players were more common at this time. The option remains that a CD can be produced later, given that all material was recorded digitally.

A VHS video of 38 minutes duration was produced. After an Introduction (2 minutes), the video was divided into 5 steps – Virus symptoms (10 minutes), Source & spread of virus (3 minutes), Vector monitoring (11 minutes), Vector management (5 minutes) and a section on putting it all together - Virus management (5 minutes). A Summary (2 minutes) was also included. Within each step the two viruses were considered separately.

Before the final editing of the video was undertaken, a draft was given to one group of potato growers for comments. The response was very positive, despite the fact that the video runs for 38 minutes. The meaning of different aspects was clear and the growers did not recommend any major changes.

The total cost of the development of the video was estimated to be $65,000. This includes $20,000 from Western Australian Potato Producers’ Committee and Horticulture Australia Limited, $20,000 for time and travel involved in the production by employees of the Department of Agriculture, WA and other public and private groups and the balance being the estimated cost over-run by the production company. To produce 250 copies of the video for WA potato growers, the individual cost was $8 per video.

Therefore, considering the total cost of production and copying, each video for a production run of 250 results in a cost per video of $268. For a distribution run of 1,000 copies, which may be required nationally, the cost per video is $73. For this latter figure, the cost of the video is in line with that of a good text book. In this regard, the total cost for this project is suggested to be good value.

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Discussion

Lessons learnt

The main lesson learnt in the production of the video was to have a well-prepared script. This is necessary both for the purpose of providing video producers with some information to be able to quote on the work. This is important because it will indicate the quality of the finished product in terms of extra graphics required as well as actual video footage. The time spent on developing a script that is near to the final version at the early stages of such a project is also valuable later to allow for the efficient making of the video. This enables a list of vision required to be drawn up, including interviews with specialists as well as interviewing growers. Much time can be saved in the field to obtaining appropriate vision, as well as drawing up a timetable if some vision can be obtained only at certain times of the year. Also, by having a complete set of vision, the job of editing can be achieved most efficiently, with minimal disruption and the need for repeat sessions in the edit room.

It is largely for this reason that the actual cost for the production of this video was exceeded, as was the timeline for the completion of this project.

Farmer’s response

As mentioned in Results, one group of growers who viewed a late draft of the video were very positive about it. Compared to the earlier video on aphid management (Berlandier, 2000), the current video includes detail on the other major virus vector group, thrips. The video also provided detail on the viruses themselves and relevant aspects of virus sources and spread that potato growers require in order to reduce the infection levels in crops. Therefore this video was seen to provide a more complete picture of the virus story in potato crops with respect to the two main insect transmitted viruses.

Video availability

Pending the acceptance of the final report, including the video itself, copies of the video will be distributed to potato growers in Western Australia.

Whether the video is made available more widely to potato growers in other Australian states will be a matter left to HAL, including the determination of its cost to growers.

As shown in the Results section, the overall cost per video for distribution in WA only is approximately $268. This reduces to $73 for national distribution. This economy of scale indicates that should similar projects be undertaken in the future, serious consideration needs to be given for funding to be provided by the Australian industry.

All digitally reorded vision used in the production of this video, as well as the actual digital version of the final video and the full script as a WORD document, may be requested from the senior author for use by others, should they desire to produce a video on the same or similar topic. Also, the script for the video is included as an Appendix in this report.

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Technology Transfer

The video was produced as a form of technology transfer to provide a self-help for WA potato growers to understand and implement management strategies to produce potato crops with minimal virus levels. The suitability of the video in this regard was indicated by the positive feedback from a group of WA potato growers who commented favourably on a near to final draft of the video.

Recommendations

Pending HAL approval of the video and its distribution to WA potato growers, a phone survey be conducted on 10% of WA potato growers six months after release of the video for feedback on their views regarding the video and whether it has helped them with managing insect transmitted viruses. Growers should be asked if they prefer receiving information in this format for such specialist areas of crop production.

If such feedback is positive, consideration should be given to using the video format for other crop management aspects.

It is recommended to HAL that the video be distributed to growers in other states as many of the principles are applicable to all potato growing regions of Australia.

Bibliography

Anon. (2001). Western Australian certified seed potato scheme (incorporating national standards). AGWEST Plant Laboratories. WA Department of Agriculture. 35 pages.

Berlandier, F.B. (2000). Aphid management for potato crops. (AustralAsia Productions P/L). Department of Agriculture, South Perth. 7.5 minutes.

Stevenson, W. R., Loria, R., Franc, G. D., Weingartner, D. P. (Eds.) (2001). Compendium of potato diseases. The American Phytopathological Society, Minnesota USA. ISBN 0-89054-275-9. 106pp.

The citation for the current video: Learmonth, Stewart; Jones, Roger; Holland, Mark. (2003). Managing virus diseases of potato crops: potato leafroll and tomato spotted wilt. Publ. Western Australian Government – Department of Agriculture. ISBN 0-9750727-0-6. 38 minutes.

Acknowledgments

The financial support of the Department of Agriculture, Western Australia, Western Australian Potato Producers’ Committee and Horticulture Australia Limited to run this project is gratefully acknowledged.

The following specialists are thanked for reviewing the early draft of the script of the video - Dr Calum Wilson, Dr Paul Horne and Françoise Berlandier. The initial draft for the video was developed in collaboration with Robert Money, who has since resigned from the WA Department of Agriculture.

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The co-operation and interest of the WA potato growers involved in the project made it that much more satisfying to produce the video. The following farmers are thanked for their individual contributions to the production of the video - Alan Darnell, Dom Della-Vedova, Laurie Eldridge, Bert Russell and Keith Taylor,

The following specialists are thanked for their assistance with discussion, reviewing and providing special components for the production of the video - Dr Alan Clift, David Cousins, Brenda Coutts, Dr Ian Dadour, Peter Dawson, Danae Harman, Lindrea Latham, John Moore, Frank O’Donnell, Dale Spencer, Len Tesoriero, Monica Thomas and Shane Trainer

The following are thanked for assistance with on-site footage for the video - Beta Spuds, Castro Farms, G. B. Bendotti & Sons, Darren Colombera, Herdsman Fresh Markets, Graham Rose, Lancelin Farms, Patrick Stevedores, Radonich Farms and Woolworths.

The following are thanked for providing their permission to use their photographs - Australian Potato Industry Council and Horticulture Australia Limited, John Hunter, Western Australian Herbarium (1998). FloraBase - Information on the Western Australian flora. Department of Conservation and Land Management. http://www.calm.wa.gov.au/science/florabase.html, Dr Marilyn Steiner, Victorian Certified Seed Potato Authority Inc., Keith Blackmore and Western Australian Plant Protection Society, Jon Dodd.

The following members of the production crew at Channel NINE, Perth are gratefully acknowledged for their long running patience in achieving the final outcome - Rex Ranieri, Commercial Production Manager; Gabrielle Gentile, Graphic Artist; Paul Baker, Computer Editing and CHANNEL NINE PRODUCTION SERVICES, PERTH.

Pat Harding is very gratefully acknowledged for the narration.

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Appendix The video script, with some notes on the vision

Managing virus diseases of potato crops:

potato leafroll and tomato spotted wilt

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INTRODUCTION – THE 5 STEPS TO MANAGING VIRUSES IN POTATOES

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VISION AUDIO

Open on vision of healthy crop

Dissolve to vision of harvester in action (try for Winter Gem).

Vision then cuts to potatoes on conveyor belt.

Symptoms of LEAFROLL virus on plants & tubers

Someone looking at a plant in a potato crop.

Split Screen:

LEAFROLL SPOTTED WILT

NEED CAPTIONS

IT’S TAKEN SOME 3 TO 4 MONTHS OF DETAILED PREPARATION & ONGOING CARE TO PRODUCE A CROP OF THIS QUALITY……..pause…….ONE THAT GUARANTEES GROWERS A GOOD RETURN ON THEIR INVESTMENT.

AN EVER PRESENT THREAT TO A POTATO GROWER’S BOTTOM LINE ARE VIRUS DISEASES.

MANY TYPES OF VIRUS CAN AFFECT POTATO CROPS. IN AUSTRALIA THERE ARE 2 OF PARTICULAR CONCERN.

THESE ARE POTATO LEAFROLL VIRUS AND TOMATO SPOTTED WILT VIRUS.

POTATO CROPS THAT ARE HEAVILY INFECTED WITH THESE VIRUSES WILL HAVE REDUCED YIELD AND THE QUALITY OF TUBERS MAY ALSO BE AFFECTED WITH INTERNAL DISORDERS.

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(PLRV side comes in first then TSWV with photos showing symptoms of each disease)

Seed potatoes in bins & ware potatoes in a retail store.

INSERT PHOTO OF COOKED FRENCH FRY INFECTED WITH PLRV

Show seed crop

Have 5 key issues as text on LHS of screen with vision on the RHS. Go through each aspect with highlighted text, then it goes dull as the next aspect is mentioned. See schematic in Section 7 for detail – repeat this schematic here.

OR

Could have relevant vision with text overlay of steps 1 to 5

ADDITIONALLY, MARKETING SEED POTATOES INFECTED WITH VIRUS WILL DAMAGE THE INDUSTRY’S REPUTATION.

TO PRODUCE HEALTHY POTATO CROPS WITH MINIMAL VIRUS LEVELS, GROWERS NEED TO FOLLOW FIVE KEY STEPS:

• RECOGNISE THE VIRUS SYMPTOMS IN POTATO CROPS

• UNDERSTAND THE SOURCES OF POTATO VIRUSES AND HOW THEY SPREAD

• MONITOR INSECT VECTORS THAT TRANSMIT POTATO VIRUSES

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Finish with vision of a healthy crop & tubers.

• MANAGE THE INSECT VECTORS THAT TRANSMIT POTATO VIRUSES

AND

• COMBINE ALL ASPECTS TO CONSIDER THE MAIN MEASURES GROWERS CAN TAKE TO MANAGE POTATO VIRUSES

THIS VIDEO DESCRIBES IN DETAIL HOW TO MINIMISE THE CHANCES OF POTATO LEAFROLL AND TOMATO SPOTTED WILT VIRUS DISEASES AFFECTING YOUR POTATO CROPS.

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STEP 1. - RECOGNISING THE VIRUS SYMPTOMS IN POTATO CROPS

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VISION AUDIO

Someone looking at a plant in an infected crop.

Schematics to help explain the differences and define:

current season or primary infection

tuber - borne or secondary infection

THE FIRST ESSENTIAL IN GROWING A POTATO CROP WHICH HAS MINIMAL INFECTION WITH EITHER POTATO LEAFROLL VIRUS OR TOMATO SPOTTED WILT VIRUS IS RECOGNISING PLANTS THAT HAVE DISEASE SYMPTOMS.

MOST VIRUSES ARE TRANSMITTED BY INSECT VECTORS. WHEN NEW INFECTION IS INTRODUCED BY SUCH INSECTS, THIS IS REFERRED TO AS CURRENT-SEASON OR PRIMARY INFECTION.

ALSO, LEAFROLL VIRUS CAN BE TRANSMITTED THROUGH PLANTING INFECTED SEED. THIS ALSO OCCURS TO A DEGREE WITH SPOTTED WILT. THIS IS REFERRED TO AS TUBER-BORNE OR SECONDARY INFECTION.

ON SCREEN – POTATO LEAFROLL VIRUS SYMPTOMS

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VISION

INFECTED PLANT WITH TUBER- BORNE PLRV INFECTION NEXT TO A HEALTHY PLANT.

Close up showing detail of symptoms of tuber-borne infection.

Scene of Dale Spencer handling an infected plant and describing his best way of identifying virus symptoms

AUDIO

WITH LEAFROLL, SYMPTOMS IN THE FOLIAGE DIFFER BETWEEN CURRENT SEASON INFECTION AND TUBER BORNE INFECTION.

WITH CURRENT SEASON INFECTION WHICH IS INTRODUCED BY APHIDS, THE FOLIAGE OF SOME VARIETIES MAY SHOW EITHER VERY MILD OR NO DISEASE SYMPTOMS, BUT OTHER VARIETIES MAY DEVELOP OBVIOUS SYMPTOMS.

TO RECOGNISE THE SYMPTOMS OF CURRENT SEASON INFECTION YOU NEED TO INSPECT THE YOUNG LEAVES, PARTICULARLY THE BASES OF THE LEAFLETS WHERE THERE MAY BE AN UPROLLING.

OFTEN THESE LEAFLET BASES CAN TURN PALE. THERE IS ALSO AN UPRIGHT APPEARANCE IN INFECTED YOUNG LEAVES.

IN SOME VARIETIES THERE IS A DISTINCT PURPLING OR REDDENING OF THE UNDERSIDE OF YOUNG LEAVES.

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INFECTED PLANT WITH CURRENT SEASON INFECTION NEXT TO A HEALTHY PLANT.

Close up showing detail of symptoms of current-season infection

Show symptoms in different varieties, if photos available.

CURRENT-SEASON SYMPTOMS RARELY SPREAD TO LOWER LEAVES.

IF INFECTION BEGINS LATE IN A CROP, CURRENT-SEASON SYMPTOMS MAY NOT APPEAR, EVEN IN SENSITIVE VARIETIES.

SO, UNLESS TUBERS ARE TESTED IN THE LABORATORY, LEAFROLL INFECTION IN SUCH SEED CROPS MAY REMAIN UNDETECTED UNTIL IT’S OBSERVED IN THE NEXT CROP.

TO EXPLAIN THE SYMPTOMS OF PLANTS INFECTED BY TUBER-BORNE DISEASE OR SECONDARY INFECTION, IS PLANT VIROLOGIST WITH THE WESTERN AUSTRALIAN DEPARTMENT OF AGRICULTURE DR ROGER JONES:

“YOU CAN SEE IN THIS SPECIMEN FROM THE FIELD I AM HOLDING HERE, THE TYPICALLY ROLLED LEAVES FROM WHICH THE VIRUS GETS ITS NAME LEAF ROLL. AND THESE ARE TYPICALLY ASSOCIATED WITH STIFFENING WHICH YOU DON’’T FIND WHEN YOU HAVE PHYSIOLOGICAL ROLLING OCCURING IN THE FIELD; WHERE PHYSIOLOGICAL ROLLING IS SOFT TO THE TOUCH. THESE ROLLING SYMPTOMS ARE OFTEN ASSOCIATED WITH PURPLING ON THE UNDERSIDE OF THE LEAF AND

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Vision of seed-borne infection.

SPECIMEN

REDDING SYMPTOMS BUT THOSE DEPEND ON THE VARIETY. THE VARIETY HERE BEING RUSSET BURBANK WHICH DOESN’T DO THAT. WHAT WE HAVE IN THE POT HERE IS AN INFECTED PLANT THAT HAS BEEN GROWN FROM A TUBER AND AGAIN YOU CAN SEE THE TYPICAL ROLLING OF THE LEAVES OFTEN IN A SORT OF SHOVEL SHAPE. AGAIN STIFF TO THE TOUCH DISTINGUISHING FROM PHYSIOLOGICAL ROLLING”.

RESUME THE AUDIO HERE.

PLANTS WITH TUBER BORNE INFECTION ARE SCATTERED ACROSS A CROP. THEY ARE OFTEN MORE STUNTED THAN UNINFECTED PLANTS – SEED CROP INSPECTOR WITH AGWEST PLANT LABORATORIES DALE SPENCER DEMONSTRATES:

“THAT’S QUITE A BAD INFECTION, YOU CAN SEE THAT SMALL SECTION THERE OF 2 PLANTS HAVE GOT IT AS OPPOSED TO THIS PLANT HERE THAT’S GETTING QUITE ALONG IN ITS AGE, BUT YOU CAN SEE IN

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Show Nooksack infected plant.

COMPARISON TO THE INFECTED PLANT IT HAS QUITE A GOOD COLOUR AND THERE’S NO OBVIOUS SIGNS OF CUPPING OF THE LEAVES AND IT’S DEFINITELY NOT STUNTED. SO THAT’S QUITE A HEALTHY PLANT”.

SYMPTOMS OF LEAFROLL ARE MORE OBVIOUS IN SOME VARIETIES OF POTATOES. FOR EXAMPLE, THE FRENCH FRY VARIETY NOOKSACK AND THE FRESH MARKET VARIETY NADINE BOTH SHOW OBVIOUS SYMPTOMS WHEN INFECTED BY LEAFROLL.

(DALES SSPENCER CONTINUES):

“HERE IS QUITE A GOOD EXAMPLE OF THE SAME VARIETY, IT’S A NOOKSACK VARIETY OF POTATO AND WE DO HAVE CRUNCHING OF THE LEAVES AT THE BOTTOM OF THE PLANT. SO OBVIOUSLY THAT SEED PIECE WAS PLANTED WITH AN INFECTED LEAFROLL VIRUS”.

.

AT CERTAIN TIMES OF THE YEAR, THE SYMPTOMS ARE LESS OBVIOUS, FOR EXAMPLE, DURING COLD WEATHER.

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PLANT WITH NUTRITION DEFICIENCY

Show plants with physiological leafroll.

A NOTE OF CAUTION – OTHER FACTORS MAY CAUSE SIMILAR SYMPTOMS. HOWEVER IN MOST CASES, THE ALTERNATIVE CAUSE CAN BE DISTINGUISHED FROM LEAFROLL INFECTION.

FOR EXAMPLE, PHYSIOLOGICAL ROLLING WHICH OCCURS FOR REASONS OTHER THAN A VIRUS INFECTION, MAY RESULT IN ROLLED LOWER LEAVES BUT THESE WILL NOT HAVE THE CRISP FEEL THAT OCCURS WITH THE LEAFROLL VIRUS. ALSO, THE SYMPTOMS WILL BE REGULAR ACROSS THE CROP, COMPARED TO THE MORE TYPICALLY SCATTERED NATURE OF LEAFROLL INFECTION.

(DALE SPENCER CONTINUES)

“I’M HERE IN A QUITE A LARGE FIELD OF VELOR VARIETY POTATO. WHAT WE’VE GOT HERE IS WHAT I CALL NUTRITIONAL LEAFROLL WHICH CAN BE MISTAKEN FOR POTATO LEAFROLL VIRUS. SYMPTOMS, AS YOU CAN SEE, ARE VERY SIMILAR TO THE POTATO LEAFROLL VIRUS. CUPPED LEAVES, SOME PLANTS DO GET THIS PURPLING EFFECT ON THE UNDERSIDE PARTS OF THE LEAVES. THE NUTRIENTS HAVE RUNOUT BECAUSE THIS CROP IS GETTING TO MATURE AGE AND IT’S SUFFERING NUTRITIONAL PROBLEMS”.

RESUME THE AUDIO HERE.

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Show plants suffering from water stress.

Insert vision of Ruby Lou crop showing rolled leaves.

Show plant with an ABB chewed base.

Show vision of non-virus disease damage on MHRI

WHERE CROPS ARE WATER STRESSED AND LEAFROLLING OCCURS DUE TO WILTING, THE EFFECT IS MORE GENERAL THAN WOULD BE THE CASE IF THE CROP WAS INFECTED WITH LEAFROLL. AGAIN, THE LEAVES WILL BE SOFT TO THE TOUCH.

IN THE VARIETY RUBY LOU, LEAVES HAVE A NATURAL ROLL THAT APPEARS SIMILAR TO LEAFROLL. OF COURSE THIS WILL OCCUR ON ALL PLANTS. ALSO, THERE IS NO ASSOCIATED DISCOLOURATION OR CRISPNESS ON LEAVES.

DAMAGE TO THE BASE OF THE STEM AS A RESULT OF INSECT OR MECHANICAL DAMAGE, MAY ALSO CAUSE SYMPTOMS SIMILAR TO THOSE OF LEAFROLL. CHECKING THE STEMS WILL HELP DETERMINE IF INSECT DAMAGE IS THE CAUSE – IN THIS CASE ADULT AFRICAN BLACK BEETLES HAVE FED ON THE STEM JUST BELOW GROUND LEVEL.

DISEASES THAT AFFECT STEM TISSUE OR WIND-DAMAGE, MAY ALSO PRODUCE SIMILAR SYMPTOMS.

PLRV infected plant with small tubers.

POTATO PLANTS INFECTED EARLY IN THEIR LIFE WITH LEAFROLL YIELD LESS AS THEY SET SMALLER AND FEWER TUBERS. THIS IS THE CASE WITH THE PLANT ON THE LEFT.

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Show cut tuber from infected plant:

- fresh

- cooked

IN A FEW SENSITIVE VARIETIES SUCH AS RUSSET BURBANK, SYMPTOMS OF LEAFROLL ALSO APPEAR IN THE FLESH OF TUBERS.

WHEN CUT, SUCH TUBERS SHOW BROWN SPOTTING IN THE VEINS NEAR THE SKIN. THIS IS REFERRED TO AS NET NECROSIS.

WHEN PROCESSING VARIETIES ARE COOKED, THESE SPOTS BECOME EVEN MORE EVIDENT.

WHEN TUBERS ARE STORED, THE SYMPTOMS OF NET NECROSIS BECOME MORE SEVERE WITH TIME.

.

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ON SCREEN – TOMATO SPOTTED WILT VIRUS SYMPTOMS

Infected plant with close up of infected leaf.

Show thrips (split screen with symptoms).

INFECTED PLANT WITH CURRENT SEASON INFECTION NEXT TO A HEALTHY PLANT.

UNLIKE LEAFROLL, SPOTTED WILT IS NORMALLY SPREAD INTO A POTATO CROP BY THRIPS THAT HAVE FED ON INFECTED PLANTS NEARBY. CARRYOVER OF INFECTIONS THROUGH SEED POTATOES IS LIMITED BUT CAN BE SIGNIFICANT IN SOME SUSCEPTIBLE VARIETIES. THEREFORE SYMPTOMS ARE MAINLY FROM CURRENT SEASON INFECTION, INTRODUCED BY INVADING, VIRUS-CARYING THRIPS. TYPICALLY THIS IS SHOWN BY THE DISTRIBUTION OF INFECTION IN THE CROP - THERE WILL BE A GREATER INCIDENCE OF INFECTED PLANTS NEAR CROP MARGINS

SPOTTED WILT CAN BE A VERY SEVERE DISEASE. IN THE EARLY STAGES OF INFECTION, IT CAUSES BROWN SPOTTING ON LEAVES, WHICH LATER TURN BLACK. CONCENTRIC NECROTIC RINGS MAY APPEAR AROUND A CENTRAL NECROTIC SPOT ON LEAVES. NECROTIC STREAKS MAY APPEAR ON LEAF STALKS AND VEINS.

LATER, DIEBACK DEVELOPS IN INFFECTED SHOOTS CAUSING INDIVIDUAL STEMS TO DIE. OFTEN NOT ALL SHOOTS ON THE PLANT ARE AFFECTED. THIS IS BECAUSE THE VIRUS MAY NOT TRANSLOCATE THROUGH ALL

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Show TSWV symptoms on leaves & stems.

Photos of infected tubers.

Close-up of necrotic area on a leaf.

Show photo of tuber with concentric rings externally

STEMS.

INFECTED TUBERS MAY SHOW SEVERE BLACKENING INSIDE. THE DEGREE OF BLACKENING VARIES MARKEDLY WITH THE VARIETY AND THE AGE AT WHICH PLANTS ARE INFECTED. VARIETIES LIKE RUSSET BURBANK SHOW LITTLE OR NO BLACKENING WHILST SUSCPETIBLE VARIETIES LIKE SHEPODY AND ATLANTIC ARE PRONE TO INTERNAL DISCOLOURATION.

EXTERNAL LESIONS ON TUBERS ARE LESS COMMON THAN INTERNAL BLACKENING. IN THE VARIETY SHEPODY AN UNUSUAL SYMPTOM OF CONCENTRIC RINGS DEVELOPS ON THE SURFACE OF THE TUBER. ARCS OR RINGS MAY ALSO APPEAR IN THE FLESH.

AS WITH LEAFROLL, SYMPTOMS OF SPOTTED WILT IN TUBERS BEING STORED BECOME MORE SEVERE WITH TIME.

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Plant with early blight symptoms and TSWV symptoms.

Healthy crop.

SYMPTOMS ON FOLIAGE OF PLANTS SUSPECTED OF BEING INFECTED WITH SPOTTED WILT, MAY, IN FACT, HAVE OTHER CAUSES.

ONE OF THE MOST COMMON IS THE EARLY SIGNS OF AN INFECTION WITH THE FUNGAL DISEASE TARGET SPOT, ALSO KNOWN AS EARLY BLIGHT. THE MAIN DIFFERENCE IS THAT WITH EARLY BLIGHT, OLDER LOWER LEAVES ARE USUALLY INFECTED FIRST. DEAD AREAS OF LEAVES START AS SMALL SPOTS AND EXPAND BECOMING BROWN AND BLACK. THEY ARE CIRCULAR AT FIRST BUT EXPAND TO VEINS TAKING ON AN ANGULAR APPEARANCE. WITHIN THE DEAD LEAF TISSUE, THERE MAY BE CONCENTRIC RINGS – GIVING THIS A “BULLS EYE” EFFECT. LEAF TISSUE AROUND THE DEAD AREA IS OFTEN LIGHT YELOW. AS THE DISEASE DEVELOPS, WHOLE LEAVES DIE. ALSO, WITH EARLY BLIGHT IT IS MORE LIKELY THAT MOST OF A CROP WILL BE AFFECTED, BUT FOR SPOTTED WILT, A PATCHY DISTRIBUTION AND CONCENTRATION OF INFECTION AROUND CROP MARGINS IS MORE COMMON.

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STEP 2. – UNDERSTANDING THE SOURCES OF POTATO VIRUSES AND HOW THEY SPREAD

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VISION AUDIO

A healthy mid stage crop.

Close up of plant, close up of aphid/thrip.

TO EFFECTIVELY MANAGE INSECT TRANSMITTED VIRUSES OF POTATO CROPS, IT’S IMPORTANT FOR GROWERS TO UNDERSTAND HOW CROPS CAN BECOME INFECTED AND HOW THE VIRUSES CAN BE SPREAD THROUGH A CROP.

POTATO LEAFROLL VIRUS AND TOMATO SPOTTED WILT VIRUS CAN SURVIVE ONLY INSIDE LIVING PLANTS AND INSECT VECTORS.

ON SCREEN - SOURCES AND SPREAD OF POTATO LEAFROLL VIRUS

Show leafroll infected plants.

Show Graph of leafroll for infected and uninfected seed.

Volunteer potato plants in pasture/near a potato crop. A winged aphid.

THERE IS A VARYING DIFFERENCE IN RANGE OF PLANT SPECIES THAT LEAFROLL VIRUS CAN INFECT. FOR LEAFROLL THE PRINCIPLE SOURCE IS FROM SOWING INFECTED SEED.

ANOTHER IMPORTANT SOURCE OF LEAFROLL IS WHERE THERE ARE INFECTED VOLUNTEER POTATO PLANTS IN OR NEAR POTATO CROPS.

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Symptoms of leafroll.

Nightshade plant.

OF MUCH LESSER IMPORTANCE ARE INFECTED WEEDS AND OTHER CROPS BELONGING TO THE POTATO FAMILY. EXAMPLES INCLUDE THE WEED NIGHTSHADE, AND TOMATO AND CAPSICUM CROPS.

Shot of aphids on leaf & close up of aphids.

Repeat graphic of aphid/virus/plant.

THE ONLY WAY LEAFROLL CAN SPREAD TO UNINFECTED PLANTS IS BY THE FEEDING OF VIRUS–CARYING APHIDS. THESE INSECTS FEED BY INJECTING SALIVA INTO PLANTS AND SUCKING UP THE SAP.

Graphic of % virus over time for early Vs late season infection.

Show senescing crop.

YOUNG PLANTS ARE MOST SUSCEPTIBLE TO BEING INFECTED WITH LEAFROLL BY APHIDS AND RESULT IN THE HIGHEST PROPORTION OF INFECTED TUBERS. WHEN THE VIRUS IS INTRODUCED EARLY IN THE CROP’S LIFE, HIGH INFECTION LEVELS CAN RESULT. AS A CONSEQUENCE, YIELD LOSSES ARE HIGH. WITH LATE INFECTIONS, VIRUS LEVELS WILL BE LOW IN BOTH THE CROP CANOPY AND THE TUBERS.

AS POTATO PLANTS AGE THEIR SUSCEPTIBILITY TO INFECTION DIMINISHES. FURTHERMORE WHEN OLD POTATO PLANTS DO SUCCUMB TO INFECTION, SPREAD OF VIRUS TO THEIR TUBERS IS SLOWER THAN IN YOUNGER PLANTS AND LESS TUBERS MAY BECOME INFECTED. THIS IS CALLED MATURE PLANT RESISTANCE.

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ON SCREEN - SOURCES AND SPREAD OF TOMATO SPOTTED WILT VIRUS

VISION AUDIO

Show TSWV diseased plants. FOR THE VIRUS DISEASE SPOTTED WILT, THE MAIN INFECTION SOURCE FOR POTATO CROPS IS FROM THRIPS WHICH HAVE FED ON NEARBY INFECTED WEEDS OR OTHER SUSCEPTIBLE HOST PLANTS.

HOWEVER THE INTRODUCTION OF VIRUS CAN ALSO OCCUR FROM INFECTED SEED POTATOES. VARIETIES DIFFER GREATLY IN THEIR ABILITY TO PASS SPOTTED WILT THROUGH SEED TUBERS TO THE NEW CROP.

Show healthy potato crop and pan across to vision of the weeds capeweed & photo of sowthistle.

Insert photos of k paw, everlasting daisy & Sydney flannel flower.

UNLIKE LEAFROLL, SPOTTED WILT HAS BEEN FOUND IN OVER 1,000 SPECIES OF PLANTS. THESE INCLUDE PLANTS BOTH IN THE SAME FAMILY AS POTATO AND PLANTS FROM UNRELATED GROUPS. THIS INCLUDES MANY COMMON WEEDS SUCH AS CAPEWEED & SOWTHISTLE.

ALSO NATIVE PLANTS HAVE BEEN REPORTED TO BE HOSTS FOR SPOTTED WILT, FOR EXAMPLE KANGAROO PAW, EVERLASTING DAISY AND FLANNEL FLOWER.

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Thrips on a potato leaf in the field and magnified under a microscope – adults & nymphs.

Show lifecycle of thrips here.

Show close up of thrips again

THE VECTORS THAT CARRY THE VIRUS INTO A POTATO CROP ARE THRIPS. THESE INSECTS CAN PICK UP THE VIRUS FROM INFECTED PLANTS ONLY IN THE FIRST STAGE OF THEIR DEVELOPMENT AFTER HATCHING.

ONLY AFTER THESE INFECTED INSECTS REACH THE WINGED ADULT STAGE ARE THEY CAPABLE OF INVADING A POTATO CROP AND INTRODUCING THE VIRUS.

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STEP 3. - MONITORING INSECT VECTORS THAT TRANSMIT POTATO VIRUSES

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OPEN on vision of lush, healthy potato crop.

(DISSOLVE to vision of harvester in action.)

VISION then cuts to potatoes on conveyor to be washed and packed

Technician holding a potato leaflet; he places it under the microscope. CUT to CUT of aphid and thrip

APHIDS & THRIPS CAN INTRODUCE VIRUSES INTO POTATO CROPS LEADING TO HIGH LEVELS OF VIRUS INFECTION. MONITORING FOR THESE INSECTS IS IMPORTANT IN DECIDING WHETHER THEY ARE A THREAT TO THE HEALTH OF YOUR CROP.

ON SCREEN - MONITORING APHIDS THAT TRANSMIT POTATO LEAFROLL VIRUS

Show close up of aphids

Show close up of thrips

DISSOLVE through to vision of grower closely inspecting his crop. He stoops, pulls back to top growth, then checks the underside of the lower leaves.

4 visions:

1. red cross thru a seed potato crop

WITHOUT AN EFFECTIVE MONITORING PROGRAM, AN UNDETECTED INFESTATION OF APHIDS COULD AFFECT THE RETURN FROM YOUR CROP:

THE VIRUS INFECTION LEVEL ALLOWED IN AUSTRALIAN SEED POTATOES IS VERY LOW. APHIDS IN YOUR CROP COULD INTRODUCE DISEASE, RESULTING IN REJECTION BY AN INSPECTOR. ALSO, BASED ON

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2. Show leafroll infected plant.

3. SHOW crop spraying underway.

4. Vision shows close-up of Aphids on leaf. And sprayer moving through a crop. Show healthy crop again – high yielding thru good insect control.

SHOW aphids

Close up of aphids – show line drawings of cornicles on end of aphid body.

THE APHID INFESTATION THRESHHOLD FOR SEED CROPS ADOPTED BY THE WESTERN AUSTRALIAN SEED SCHEME, INSPECTORS CAN ALSO REJECT CROPS ON THE BASIS OF APHID OCCURRENCE.

SECONDLY, UNDETECTED APHIDS COULD LEAD TO HIGH LEAFROLL VIRUS LEVELS, SO REDUCING YIELD AND TUBER QUALITY.

THIRDLY, BY MONITORING, GROWERS CAN AVOID UNNECESSARY INSECTICIDE APPLICATIONS, THUS SAVING MONEY AND REDUCING THE USE OF CHEMICALS. MONITORING WILL ALSO CONFIRM THE EFFECTIVENESS OF SPRAYING.

AND LASTLY, GROWERS WILL BE ABLE TO BETTER TIME THEIR SPRAY APPLICATIONS FOR MAXIMUM EFFECTIVENESS TO COINCIDE WITH INSECTS ARRIVING IN THEIR CROPS AND THE CRITICAL EARLY PHASE OF VIRUS SPREAD WHEN LOW INSECT POPULATIONS MUST BE CONTROLLED.

APHIDS ARE SMALL, UP TO 2 MILLIMETRES LONG, SOFT BODIED INSECTS THAT FEED BY SUCKING SAP FROM PLANTS. THEY HAVE CORNICLES WHICH LOOK LIKE FUNNELS, ON THE END OF THEIR ABDOMEN.

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Show whitefly adults and nymph.

SHOW crop

Show aphid nymph and wingless adults.

Show many aphids on a potato leaf

CUT to close-up of each species on cue.

(AGWA to supply slides)

SHOW Cow Pea Aphid.

SHOW other three species

MATURE APHIDS MAY BE WINGED OR WINGLESS. THE IMMATURE STAGES OF WHITEFLY RESEMBLE WINGLESS APHIDS, ESPECIALLY THE SMALL IMMATURE APHIDS OR NYMPHS. BUT WHITEFLY NYMPHS ARE IMMOBILE ONCE THEY COMMENCE FEEDING.

IN LARGE NUMBERS, FEEDING BY APHIDS MAY CAUSE PLANTS TO WILT, PREVENTING THE DEVELOPMENT OF HEALTHY CROPS. BUT THIS IS VERY UNCOMMON AND I’IS THEIR ROLE AS A POTENTIAL CARRIER OF PLANT VIRUSES THAT MAKE THEM IMPORTANT.

THERE ARE OVER 140 SPECIES OF APHIDS IN AUSTRALIA, BUT ONLY 4 SPECIES ATTACK POTATOES.

THEY ARE THE GREEN PEACH APHID, THE COWPEA APHID, THE POTATO APHID AND THE FOXGLOVE APHID.

WITH THE EXCEPTION OF THE COWPEA APHID, WHICH IS BLACK OR DARK GREY IN COLOUR, THE GREEN PEACH, POTATO AND FOXGLOVE APHIDS ARE GREENISH-YELLOW. ALSO, ONLY THE GREEN PEACH APHID CAN BE FOUND ON

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SHOW GPA’s

DISSOLVE from CU of GPA’s to SLIDES of Canola, lupin crops and nightshade.

Show sprayer

CUT to AGWA lab. Show technician at microscope. CUT to vision of GPA’s.

THE LOWER LEAVES OF POTATO PLANTS.

THIS IS CRITICAL IN ACCURATE MONITORING FOR GREEN PEACH APHID.

IF APHIDS ARE FOUND IN THE UPPER, NEWER GROWTH OF A POTATO PLANT, THEY ARE UNLIKELY TO BE GREEN PEACH APHID.

THE GREEN PEACH APHID IS THE CAUSE OF GREATEST CONCERN FOR POTATO GROWERS BECAUSE IT IS THE MOST EFFICIENT VECTOR OF THE POTATO LEAFROLL VIRUS. IT’S ALSO THE MOST COMMON APHID FOUND IN POTATO CROPS

THE GREEN PEACH APHID DOESN’T DEPEND SOLELY ON POTATO PLANTS FOR ITS SURVIAL. ITS DIET INCLUDES A WIDE VARIETY OF PLANTS INCLUDING CANOLA, LUPINS AND WEEDS SUCH AS NIGHTSHADE. IT’S ALSO HARDER TO CONTROL. SOME POPULATIONS HAVE DEVELOPED RESISTANCE TO A NUMBER OF INSECTICIDES.

APHID SURVIVAL AND POPULATION GROWTH IS LARGELY INFLUENCED BY ENVIRONMENTAL CONDITIONS, PARTICULARLY TEMPERATURE.

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Cut to grower grab with Alan Darnell

SHOW graph of seasonal population changes

CUT to vision of healthy potato crop. DISSOLVE thru to vision of GPA infestation.

CUT to WS of crops.

CUT to close-up of plants, wind blowing leaves, sun glowing thru undersides

POTATO GROWER ALAN DARNELL DISCUSSES HIS EXPERIENCES WITH VIRUSES IN POTATO CROPS:

“OVER THE LAST 10 YEARS OR SO THE AGRICULTURE DEPARTMENT IN WESTERN AUSTRALIA HAVE DONE APHID MONITORING TRIALS AND WE HAVE ISOLATED A SLOT IN THE TIME OF THE YEAR THAT ALLOWS VERY FEW APHIDS IN THIS AREA. SO WE TRY TO ONLY HAVE OUR POTATO CROPS GREEN DURING THOSE MONTHS AND THEY ARE FROM NOVEMBER, DECEMBER, JANUARY AND FEBRUARY. ANY CROPS THAT WE HAVE GREEN INTO LATE MARCH WOULD NEED TO BE CAREFULLY MONITORED FOR ANY INCREASE IN APHID NUMBERS”.

INFESTATIONS OF APHIDS START WHEN A FEW FLY INTO YOUR CROP.

THEIR JOURNEY MAY HAVE STARTED ONLY A FEW METRES AWAY OR, ASSISTED BY PREVAILING WINDS, UP TO SEVERAL HUNDRED KILOMETRES AWAY.

IN IDEAL CONDITIONS, A SINGLE APHID CAN GIVE RISE TO A DAMAGING POPULATION IN 4 TO 6 WEEKS.

TO KEEP THESE PESTS IN CHECK, WE RECOMMEND THAT YOU INITIATE AND MAINTAIN A REGULAR SCHEDULE OF CROP MONITORING

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SHOW sun, trees, dried grass

CUT to AGWA lab. SHOW GPA’s in action

CUT to vision of GPA infestation

Show winged aphid

CUT to WS of paddocks adjacent to potato crop. SHOW Nightshade

CUT to freeze-frame of leaf. CAPTIONS label ‘leaf’ and ‘leaflets’.

CUT to vision of small GPA colony

DISSOLVE thru to vision of large GPA colony.

CUT to grower checking crop

AND RECORD KEEPING. THIS CAN BE DONE BY THE GROWER, AN EMPLOYEE OR A CROP SCOUT.

SCHEDULED SPRAYING CAN BE A WASTE OF MONEY, AS APHIDS ARE NOT ALWAYS PRESENT. ALSO, REGULAR SPRAYING COULD RESULT IN AN EXPLOSION OF APHID NUMBERS IF NATURAL CONTROL AGENTS ARE KILLED.

REGULAR CROP MONITORING IS THE KEY TO A SUCCESSFUL APHID MANAGEMENT PROGRAM.

CROP MONITORING SHOULD BE UNDERTAKEN WEEKLY, COMMENCING AT CROP EMERGENCE.

AT LEAST A TOTAL OF 50 LOWER LEAVES ON SEPARATE PLANTS SHOULD BE EXAMINED PER PLANTING. THE WHOLE LEAF NEEDS TO BE CHECKED FOR SIGNS OF INFESTATION.

AS PLANTS AT THE EDGES OF YOUR CROP ARE MOST LIKELY TO BE COLONISED FIRST, IT’S NECESSARY TO INCLUDE THESE IN THE MONITORING.

THERE IS NO SET PATTERN FOR MONITORING A CROP.

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CUT to CU of leaves, clear of aphids

CUT to WS of crop.

.

DISSOLVE to vision of crop

ONE EXAMPLE IS TO FOLLOW A TRIANGULAR PATH THROUGH THE CROP UP TO ROW CLOSURE. IN THIS WAY THE MONITORING IS VERY REPRESENTATIVE, INCLUDING AN EDGE AS WELL AS LOOKING ACROSS THE CROP AREA.

OTHER TRANSECTS SUCH AS ALONG ROWS MAY ALSO BE USED.

AFTER ROW CLOSURE, TO AVOID DAMAGE TO THE CROP FROM WALKING THROUGH IT, A SUGGESTED MONITORING PATH IS TO CHECK FOUR SIDES OF A CROP. AT EACH SIDE, CHECK PLANTS ON THE EDGE, THEN MOVE 10 TO 20 PACES INTO THE CROP AND CHECK AGAIN. THEN MOVE ON TO THE NEXT SIDE.

AGAIN, CHECK AT LEAST A TOTAL 50 LOWER LEAVES ON SEPARATE PLANTS PER PLANTING.

AS A CROP BEGINS TO DIE OFF BUT THE LEAVES ARE STILL GREEN, THE MONITORING PATH CAN REVERT TO TRANSECT SAMPLING, OR FOLLOW CROP ROWS.

IT’S A GOOD IDEA TO RECORD THE NUMBER OF LEAVES INFESTED. THIS SHOULD INCLUDE BOTH WINGED AND WINGLESS APHIDS, WHICH CONFIRMS THEY HAVE BRED

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CUT to grower walking into crop, stopping to check, taking notes.

CUT to CU of hands parting leaves.

CUT to CU of leaf

CUT to grower in crop

CUT to grower taking notes.

CUT to grower walking into crop, checking plants.

CONTINUE with vision of grower monitoring crop

DISSOLVE to WS of healthy crop

IN THE CROP.

A PILOT COMMERCIAL PEST MONITORING PROGRAM RUN BY THE WESTERN AUSTRALIAN DEPARTMENT OF AGRICULTURE HAS ESTIMATED THAT THE COST OF MONITORING A 4 HA CROP OVER A SEASON, WAS EQUIVALENT TO ABOUT THREE APPLICATIONS OF INSECTICIDE. MONITORING IS A FINANCIALLY VIABLE OPTION TO REGULAR SPRAYING.

EVEN WHEN USING SEED POTATOES PRODUCED UNDER AN APPROVED CERTIFICATION SCHEME, GROWERS PRODUCING COMMERCIAL POTATO CROPS NEED TO BE CONCERNED ABOUT LEAFROLL INFECTION AND SPREAD. CERTIFIED SEED STANDARDS ALLOW FOR VERY LOW LEVELS OF VIRUS INFECTION. THEREFORE, EARLY APHIDS MAY STILL BE IMPORTANT AND CONSCIENTIOUS ROUGING OF ANY INFECTED PLANTS AND APPLYING INSECTICIDES TO CONTROL APHIDS MAY STILL BE NECESSARY.

THERE IS A NUMBER OF NATURAL BILOGICAL CONTROL AGENTS THAT KEEP APHID NUMBERS DOWN. IF THESE AGENTS ARE PRESENT IN SUFFICIENT NUMBERS, SPRAYING APHIDS WILL NOT BE NECESSARY.

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ON SCREEN - MONITORING THRIPS THAT TRANSMIT TOMATO SPOTTED WILT VIRUS

Thrips on potato leaves.

Insert photos of thrip effects on leaf growth.

Vision of thrips on leaves.

Show photos of other species

THE OTHER PRINCIPAL GROUP OF INSECTS THAT TRANSMIT VIRUS IN POTATO CROPS IS THRIPS.

THRIPS ARE SMALL ELONGATE INSECTS, AT AROUND 2 MILLIMETRES LONG. ADULTS HAVE FEATHER-LIKE WINGS HELD OVER THEIR BACK. THE IMMATURE NYMPHS ARE A SMALLER, PALE, WINGLESS VERSION OF ADULTS. THEY FEED BY RASPING PLANT TISSUE AND LAPPING UP THE SAP.

IN LARGE NUMBERS ON YOUNG PLANTS, THEY CAUSE LEAVES TO TAKE ON A SILVER, DISTORTED APPEARANCE AND CAN RESTRICT PLANT GROWTH. THEY CAUSE LITTLE DAMAGE TO ESTABLISHED PLANTS. IT IS THEIR ROLE AS A POTENTIAL CARRIER OF SPOTTED WILT THAT MAKE THEM IMPORTANT.

THERE ARE MANY SPECIES OF THRIPS IN AUSTRALIA, BUT ONLY 3 ARE CAPABLE OF INTRODUCING SPOTTED WILT VIRUS INTO POTATO CROPS.

THESE ARE WESTERN FLOWER THRIPS, ONION THRIPS & TOMATO THRIPS.

THE MOST COMMON OF THESE IN POTATO CROPS IS ONION THRIPS, WITH TOMATO THRIPS BEING LESS COMMON

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More vision of thrips on leaves.

Insert graphic of thrip seasonal abundance.

AND WESTERN FLOWER THRIPS THE LEAST ABUNDANT.

WESTERN FLOWER THRIPS SPREAD THE VIRUS MORE EFFICIENTLY. HOWEVER THIS SPECIES HAS ONLY BEEN RECORDED IN AUSTRALIA SINCE 1992. WESTERN FLOWER THRIPS HAS NOT BEEN RECORDED FROM ALL POTATO GROWING DISTRICTS IN AUSTRALIA, OR FIELD CROPS IN TASMANIA. CHECK WITH YOUR CONSULTANT OR AUTHORITY AS TO WHETHER THE THRIP OCCURS IN YOUR AREA. IT’S NOT A COMMON THRIP IN POTATOES, PREFERRING OTHER VEGETABLE AND ORNAMENTAL CROPS.

THESE THREE SPECIES OF VECTOR THRIPS AND NON-VECTOR SPECIES ARE DIFFICULT TO DISTINGUISH WITHOUT THE AID OF A POWERFUL MICROSCOPE. TO CONFIRM THE IDENTITY OF THRIPS, SPECIMENS SHOULD BE COLLECTED AND SENT TO A SPECIALIST.

LIKE APHIDS, THRIPS DON’T DEPEND SOLELY ON POTATOES FOR THEIR SURVIVAL. THEY FEED ON A WIDE VARIETY OF PLANTS INCLUDING OTHER CROPS, ORNAMENTAL PLANTS AND WEEDS.

IN POTATO CROPS, THRIPS FEED ON BOTH LEAVES AND FLOWERS.

THRIPS CAN OCCUR IN POTATO CROPS FROM SPRING TO AUTUMN, HOWEVER THEIR NUMBERS MAY BE REDUCED IN

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Show crop edge and distant vision of a potato crop – to indicate distant source and wind as an aid to movement.

Show potato leaf/monitoring again and tapping flowers into an ice cream container.

Show white sticky trap.

SUMMER BY PERIODS OF HOT WEATHER.

THRIPS ARE RELATIVELY WEAK FLIERS AND RELY ON WIND TO AID THEIR DISPERSAL. INVASION OF POTATO CROPS COULD HAVE STARTED ONLY A FEW METRES FROM YOUR CROP OR, ASSISTED BY PREVAILING WINDS, MANY KILOMETRES AWAY.

IN AUSTRALIA, POTATO CROPS HAVE BEEN INFECTED MORE COMMONLY WITH LEAFROLL VIRUS - SPOTTED WILT, CARRIED AND SPREAD BY THRIPS, HAS BEEN LESS COMMON.

THEREFORE, MONITORING FOR THRIPS IS MORE IMPORTANT IN SOME AREAS THAN OTHERS – CHECK ON THE HISTORY OF SPOTTED WILT IN YOUR DISTRICT BY CONTACTING THE SEED CERTIFICATION AUTHORITY, AGRICULTURAL DIAGNOSTIC LABORATORY OR PRIVATE CONSULTANT IN YOUR DISTRICT.

TO MONITOR FOR THRIPS, LEAVES EXAMINED WHILE MONITORING FOR APHIDS HAVE BEEN FOUND TO BE REPRESENTATIVE FOR THRIPS. BUT BECAUSE THRIPS ALSO FEED IN FLOWERS, THESE SHOULD ALSO BE CHECKED. TAPPING LEAVES OR FLOWERS OVER A LIGHT COLOURED ICE CREAM CONTAINER IS A VERY USEFUL METHOD FOR FINDING THRIPS.

ANOTHER TOOL THAT MAY HELP WITH

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Show virus symptoms.

MONITORING THRIPS, IS A STICKY TRAP. THESE INDICATE THE NUMBERS AND SPECIES OF THRIPS FLYING AROUND YOUR CROP, BUT IT’S DIFFICULT TO IDENTIFY THE SPECIES CAUGHT. DISCUSS USING THIS METHOD WITH YOUR LOCAL AUTHORITY OR CROP SCOUT.

MANAGING SPOTTED WILT VIRUS DEPENDS MORE ON MINIMISING THE SOURCE OF THE VIRUS AND NOT ON CONTROLLING THRIPS WITH INSECTICIDES. NEVERTHELESS, GROWERS SHOULD BE AWARE OF THE PRESENCE OF THRIPS IN THEIR CROPS SHOULD SPOTTED WILT BECOME A PROBLEM AS THRIPS BREEDING WITHIN THE CROP MIGHT SPREAD INFECTION TO HEALTHY PLANTS.

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STEP 4. - MANAGING THE INSECT VECTORS THAT TRANSMIT POTATO VIRUSES

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ON SCREEN - MANAGING APHIDS - THE VECTORS THAT TRANSMIT POTATO LEAFROLL VIRUS

VISION AUDIO

Continue with vision of infested leaf.

Graphic of aphid numbers and virus level in crop.

AFTER MONITORING YOUR CROP AND FINDING APHIDS, IT DOESN’T ALWAYS MEAN THAT YOU NEED TO SPRAY.

THE PRESENCE OF APHIDS DOESN’T NECESSARILY MEAN THAT AN INFECTION WITH LEAFROLL WILL OCCUR. THE APHIDS NEED TO HAVE ACQUIRED THE VIRUS FROM A SOURCE BEFORE IT CAN BE TRSNSMITTED. THE RESULTS OF A PROGRAM WHERE MONITORING APHIDS AND VIRUS LEVELS IN COMMERCIAL CROPS HAS SHOWN THAT ONLY IF THE SEED POTATOES OR AN ALTERNATIVE SOURCE NEARBY ARE INFECTED WITH LEAFROLL VIRUS, WILL THE INFECTION IN A CROP BUILD UP TO LEVELS THAT CAN AFFECT QUALITY AND YIELD.

WHEN APHIDS ARE FOUND IN A POTATO CROP, THE NEED TO SPRAY THEM DEPENDS ON WHETHER THE CROP IS TO BE GROWN FOR SEED.

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Person monitoring and show aphids; weeds adjacent to potato crop.

Spray rig going through a crop.

Insert graphic of early Vs late crop infection with PLRV.

Virus infected plant.

Show a leaf with few aphids (canola leaf).

Heavily infested leaf – with aphids.

FOR SEED CROPS, THE THRESHHOLD FOR SPRAYING GREEN PEACH APHIDS IS QUITE LOW. THIS IS ESPECIALLY THE CASE IN YOUNG CROPS, WHICH ARE MOST SUSECPTIBLE TO BEING INFECTED WITH VIRUS. A SMALL INFESTATION IN THE EARLY STAGES OF A CROP HAS THE CHANCE TO BUILD UP AND SPREAD VIRUS THROUGHOUT THE CROP, RESULTING IN HIGH LEVELS OF VIRUS INFECTION. SEED GROWERS CANNOT AFFORD TO JEAPODISE THE QUALITY OF THEIR CROP.

THE THRESHHOLD IN THE WESTERN AUSTRALIAN SEED SCHEME FOR SPRAYING IS AT LEAST 5 PERCENT OF LEAVES SAMPLED ARE INFESTED WITH APHIDS, INCLUDING WINGLESS APHIDS - CONFIRMING THEY HAVE BRED IN THE CROP.

CHECK WITH YOUR LOCAL SEED CERTIFICATION AUTHORITY FOR THEIR RECOMMENDATION.

FOR COMMERCIAL CROPS GROWN FOR HUMAN CONSUMPTION AND WHERE CERTIFIED SEED HAS BEEN USED FOR PLANTING, APHIDS ARE NORMALLY ONLY REGARDED AS BEING IMPORTANT IF THEIR NUMBERS ARE HIGH ENOUGH TO CAUSE FEEDING DAMAGE. THIS IS MOST LIKELY TO OCCUR IF A CROP IS INFESTED IN THE EARLY STAGES OF GROWTH. BUT THE RANGE OF NATURAL CONTROL AGENTS THAT ATTACK APHIDS MAY MEAN CONTROL IS NOT NECESSARY.

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Vision of diseased aphids

Wasp and mummy.

LADYBIRD

HOVER FLY

DAMSEL BUG

LACE WING LARVA

VISION OF OTHER INSECT PESTS AND SPRAY RIG.

THE PRESENCE OF THESE AGENTS AS WELL AS THE PESTS NEED TO BE CONSIDERED.

THESE BENEFICIAL AGENTS INCLUDE

• FUNGAL DISEASE;

• WASP PARASITES – THE ADULT WASP LAYS AN EGG INSIDE THE APHID. THE WASP GRUB FEEDS ON THE APHID EVENTUALLY KILLING IT. THE SHINY BROWN SHELL OF THE PARASITISED APHID IS CALLED A MUMMY. THE NEW ADULT WASP PARASITE CHEWS AN EMERGENCE HOLE IN THE WALL OF THE MUMMY;

AND INSECT PREDATORS SUCH AS:

• LADYBIRD BEETLES;

• HOVERFLY LARVAE;

• DAMSEL BUGS AND;

• LACEWINGS.

THERE ARE OTHER FOLIAGE FEEDING INSECTS THAT ATTACK POTATOES.

IF INSECTICIDES ARE APPLIED TO CONTROL THEM, THIS MAY RESULT IN THE DEATH OF THE APHID NATURAL ENEMIES. THIS CAN LEAD TO AN EXPLOSION IN APHID

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Other foliar pests – looper, potato moth

NUMBERS.

SO CARE SHOULD BE TAKEN BEFORE DECIDING TO APPLY INSECTICIDES. IF YOU HAVE DECIDED TO SPRAY, CONSIDER A SOFT OPTION SUCH AS:

• AN APHID SPECIFIC INSECTICIDE;

• BT - A COMMERCIALLY AVAILABLE BACTERIAL DISEASE WHICH CONTROLS LOOPERS;

• AND BAIT FOR VEGETABLE BEETLE OR WINGLESS GRASSHOPPER.

BY FOLLOWING THESE GUIDELINES, APHID MANAGEMENT CAN BE ENHANCED BY THE BENEFICIAL AGENTS AND THE USE OF BROAD SPECTRUM INSECTICIDESS CAN BE AVOIDED OR MINIMISED.

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ON SCREEN - MANAGING THRIPS - THE VECTORS THAT TRANSMIT TOMATO SPOTED WILT VIRUS

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Show photos of weeds, separate or within potato crops.

Show photos of thrip affected leaves.

Show vision of thrips and TSWV symptoms.

Show spray rig.

TO MINIMISE THE RISK OF INTRODUCTION AND TRANSMISSION OF SPOTTED WILT BY THRIPS, IT IS IMPORTANT TO REMOVE SOURCES OF THE VIRUS RATHER THAN ATTEMPT TO REDUCE THE NUMBER OF INSECTS.

AS WELL AS TRANSMITTING VIRUS, WHEN THRIPS ARE PRESENT IN LARGE NUMBERS IN NEWLY EMERGED CROPS, THEY MAY REDUCE PLANT VIGOUR. IN SUCH SITUATIONS INSECTICIDES WOULD BE REQUIRED. BUT IN GENERAL, THRIPS DO NOT REQUIRE CONTROL.

HOWEVER IT IS IMPORTANT TO NOTE THEIR OCCURRENCE WHEN MONITORING BECAUSE OF THEIR ABILITY TO INTRODUCE AND TRANSMIT DISEASE.

UNLIKE APHIDS, THERE ARE FEWER NATUAL CONTROL AGENTS OF THRIPS. IF REQUIRED, INSECTICIDES WOULD BE THE MAIN METHOD OF CONTROLLING THRIPS, BUT GROWERS WOULD NEED TO BE AWARE THAT REINVASION FROM SOURCES EXTERNAL TO THE POTATO CROP CAN OCCUR. ALSO, MANY OF THE INSECTICIDES USED TO CONTROL THRIPS WOULD KILL BENEFICIAL AGENTS THAT MAY BE CONTROLLING OTHER PESTS.

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Show monitoring.

IN OTHER HORTICULTURAL CROPS WHERE WESTERN FLOWER THRIPS HAS BECOME AN INPORTANT PEST, INSECTICIDE RESISTANCE MANAGEMENT STRATEGIES HAVE BEEN DEVELOPED. SO FAR IT HAS NOT BEEN NECESSARY TO INTRODUCE SUCH MEASURES FOR POTATO CROPS.

THERE ARE NO ACTION THRESHHOLDS FOR DECIDING WHETHER THRIPS NEED TO BE SPRAYED. THEREFORE, IT IS IMPORTANT TO KNOW WHAT INSECTS ARE PRESENT IN YOUR CROP AND TO KEEP UP TO DATE WITH THE STATUS OF THRIPS AND VIRUS INFECTIONS IN YOUR DISTRICT.

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STEP 5. - PUTTING IT ALL TOGETHER - MEASURES GROWERS CAN TAKE TO MANAGE POTATO VIRUSES

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VISION AUDIO

Excerpts from vision below for this section.

THE EMPHASIS HERE IS ON AVOIDING VIRUS SOUCES IN OR NEAR YOUR CROP AS WELL AS MONITORING FOR THE INSECT VECTORS THAT TRANSMIT THESE DISEASES.

Weeds in & around potato crop.

Volunteer potato in pasture paddock.

Show sheep in pasture paddock.

Vision of crops near each other and sequential crops in the same paddock.

HAVING SELECTED A SITE FOR YOUR POTATO CROP, BE AWARE OF POSSIBLE EXTERNAL SOURCES OF VIRUS – SUCH AS WEEDS AND VOLUNTEER POTATO PLANTS BOTH IN AND AROUND THE FUTURE CROP.

THESE SHOULD BE SPRAYED OFF OR ELIMATED IN SOME OTHER WAY SUCH AS WITH CULTIVATION OR HEAVY GRAZING.

THERE IS ALSO A RISK OF APHIDS OR THRIPS INTRODUCING VIRUS TO A POTATO CROP FROM OTHER CROPS BEING GROWN NEARBY OR ADJACENT EARLIER PLANTED CROPS.

SUCH SITUATIONS SHOULD BE TAKEN INTO ACCOUNT WHEN SELECTING A PLANTING SITE.

WE WILL NOW LOOK AT SEED POTATO PRODUCTION AND THEN CONSIDER THE SITUATION IN COMMERCIAL POTATO CROPS

56

Scanned lab scene of tissue culture and glasshouse with mini-tubers.

Show seed crops in the field.

Someone monitoring a crop for insects.

Growers walking thru a young crop ROGUING.

COMMERCIAL POTATO CROPS.

SEED POTATO GROWERS ADOPT THE CLEAN PIPELINE APPROACH TO PRODUCE QUALITY SEED.

THE SEED PRODUCTION CYCLE STARTS WITH PATHOGEN-TESTED MINI TUBERS. THESE ARE PRODUCED UNDER HIGH-HEALTH, CONTROLLED CONDITIONS IN LABORATORIES AND GLASSHOUSES.

THIS GENERATION “ZERO” MATERIAL IS THE STARTING POINT FOR BULKING UP ON SEED GROWERS’ PROPERTIES. THIS BULKING UP PROCESS IS RESTRICTED TO A LIMITED NUMBER OF CROPS OR GENERATIONS.

THE CROP IS MONITORED FOR INSECT VECTORS, COMMENCING AT CROP EMERGENCE AND CONTINUING THROUGH TO HARVEST, AS DISCUSSED IN AN EARLIER SECTION OF THIS VIDEO.

HAVING DEALT WITH ANY PLANTS THAT WERE A POSSIBLE SOURCE OF VIRUS OUTSIDE THE CROP AREA, THE PRESENCE OF INFECTED PLANTS WITHIN THE CROP IS THE MOST IMPORTANT SOURCE OF VIRUSES. THE BEST METHOD OF CONTROL IS THROUGH THE REMOVAL OF THESE PLANTS BY THE PROCESS OF ROGUING.

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Show symptoms on young plant’s lower leaves.

More vision of a ROGUING team walking thru a crop.

Vision of grower plus others walking & talking about possible plant problems.

ROGUING COMMENCES 2 TO 3 WEEKS AFTER CROP EMERGENCE AND CONTINUES UNTIL ROW CLOSURE. BY ROGUING CROPS UP TO THIS STAGE, ANY DELAY IN PLANTS EXPRESSING VIRUS SYMPTOMS WILL BE ACCOUNTED FOR. AFTER ROW CLOSURE, SYMPTOMS OF LEAFROLL ON THE LOWER LEAVES AND THE STUNTED SPOTTED WILT INFECTED PLANTS CANNOT BE SEEN READILY.

FURTHERMORE, AFTER THIS TIME TARGET SPOT (OR EARLY BLIGHT) IS MORE PREVELANT MAKING SPOTTED WILT DIFFICULT TO IDENTIFY.

ROGUING IS BEST UNDERTAKEN BY A TEAM THAT INVOLVES AT LEAST ONE EXPERIENCED MEMBER. THE TEAM SHOULD WALK ABREAST ABOUT 3 ROWS APART.

Vision demonstrating best conditions CONDITIONS THAT ARE MOST SUITABLE FOR RECOGNISING PROBLEM PLANTS ARE:

• EARLY MORNING OR ON OVERCAST DAYS.

• THERE SHOULD BE LITTLE OR NO WIND.

• DON’T ROGUE FOR MORE THAN 3 TO 4 HOURS AT A TIME TO MAINTAIN EFFICIENCY.

• PLANTS SHOULD NOT BE WILTING.

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• LOOK AHEAD 5 TO 10 METERS RATHER THAN STRAIGHT DOWN AND PREFERABLY WITH THE SUN BEHIND YOU.

Grower pulling up a rogued plant and putting it and its attached tubers into a bag. Go thru the soil to check that all tubers have been removed.

Show vision of aphid/thrip infested leaves.

WHEN A PLANT NEEDS TO BE ROGUED, IT IS IMPORTANT TO REMOVE ANY TUBERS AS WELL. PLACE PLANTS AND TUBERS IN A BAG TO REMOVE THEM FROM THE FIELD, SO AS TO AVOID TRANSFER OF ANY APHIDS OR THRIPS FROM THE INFECTED PLANT TO HEATHY ONES, AND TO REMOVE ANY POTENTIALLY INFECTED TUBERS.

FOR EARLY GENERATION SEED, SOME GROWERS INCREASE THE SETT SPACING SO THAT THE LOWER LEAVES CAN BE SEEN MORE EASILY.

Inspector going through a crop

Insert photo of front cover of National Standards book.

SEED POTATOES ARE PRODUCED UNDER NATIONAL SEED CERTIFICATION STANDARDS. ALL SEED CROPS ARE INSPECTED TWICE – ONCE JUST BEFORE ROW CLOSURE AND AGAIN WELL INTO FULL CANOPY CLOSURE AND BEFORE CROP DIE OFF.

THE ONUS IS ON THE GROWER TO REMOVE INFECTED PLANTS BEFORE CROPS ARE INSPECTED.

IN CASES WHERE THE INSPECTOR OR GROWER SUSPECTS PLANTS ARE INFECTED WITH VIRUS, THEY MUST BE REMOVED WITHOUT DELAY.

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Vision of lab testing procedures – include key aspects only.

LEAF OR TUBER SAMPLES CAN BE SENT FOR LABORATORY TESTING TO CONFIRM THE PRESENCE OF INFECTION IN LEAF OR TUBER SAMPLES. THESE ARE TESTS THAT USE SPECIAL CHEMICALS THAT REACT WITH THE SPECIFIC VIRUS IF IT’S PRESENT.

THIS REACTION PRODUCES A COLOUR CHANGE THAT CAN BE MEASURED. WHEN SUCH TESTS ARE UNDERTAKEN, THE PROCEDURE IS VERIFIED BY HAVING A KNOWN POSITIVE TEST SAMPLE INCLUDED.

Vision of large commercial crop.

Seed potato certificate.

Show young aphid infested crop.

WE NOW CONSIDER APPROPRIATE MANAGEMENT PRACTICES TO LIMIT VIRUS IN COMMERCIAL POTATO CROPS.

A GOOD START IS TO BUY SEED FROM A GROWER PARTICIPATING IN AN OFFICIAL SEED CERTIFICATION SCHEME.

BY STARTING WITH SEED OF MINIMAL LEAFROLL CONTENT, APHIDS WILL NOT NORMALLY REQUIRE CONTROL IN COMMERCIAL CROPS. POTATO PLANTS CAN TOLERATE REASONABLY HIGH INFESTATION LEVELS OF APHIDS BEFORE YIELD IS AFFECTED. ONLY WITH EARLY APHID INFESTATIONS AND IN THE ABSENCE OF NATURAL CONTROL AGENTS WILL AN APPLICATION OF INSECTICIDE NEED TO BE

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Cut back to large healthy crop

CONSIDERED.

SIMILARLY BY USING CERTIFIED SEED, THE INCIDENCE OF TUBER-BORNE INFECTION OF SPOTTED WILT WILL BE MINIMISED.

POTATO GROWER KEITH TAYLOR SUMS UP HIS EXPERIENCES WITH MANAGING VIRUSES IN POTATO CROPS:

“IN SUMMARY THE IMPORTANT STEPS FOR ME ARE:

• HAVING GOOD SEED FROM A GROWER I CAN TRUST;

• REASONABLE HYGIENE IN THE CROP – WE CAN DO BETTER THERE IF WE NEEDED TO;

• REDUCE THE PRESSURE FROM THE DISEASES BY KEEPING DOWN VOLUNTEERS, STICKING TO AS LONG A ROTATION AS WE CAN AND USING ALL METHODS POSSIBLE TO REDUCE THE DISEASE PRESSURE. NOT JUST SPRAYING BUT ALL METHODS TOO”.

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SUMMARY - THE 5 STEPS TO MANAGING VIRUSES IN POTATOES

62

VISION AUDIO

THE AIM OF THIS VIDEO HAS BEEN TO OUTLINE THE STEPS INVOLVED IN PRODUCING QUALITY POTATO CROPS WITH MINIMAL VIRUS LEVELS.

Flow diagram - with arrows between the steps or number the steps to show the clean pipeline – see below. Same or different screens. Include vision to support main points – repeat prime shots from individual sections.

1. labs

2. seed crop

3. inspector

4. commercial large potato crop

THESE STEPS ARE:

• RECOGNISE THE VIRUS SYMPTOMS OF INFECTED PLANTS

• HAVE A GOOD UNDERSTANDING OF VIRUS SOURCES & HOW VIRUSES ARE SPREAD

• UNDERTAKE REGULAR MONITORING OF VECTORS AND OTHER INSECTS IN POTATO CROPS

• APPROPRIATE VECTOR MANAGEMENT AND WITH THE INTEGRATION OF ALL THIS INFORMATION TO

• IMPLEMENT EFFECTIVE AND EFFICIENT VIRUS MANAGEMENT TO PRODUCE HEALTHY POTATO CROPS.

Healthy crops

GROWING CROPS WITH MINIMAL VIRUS LEVELS IS GOOD FOR THE INDUSTRY.

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No spray rigs – show beneficial insects; clean & green

Tubers loaded into bins/tubers & in packing shed

Tubers in supermarket shelves & French fries in take away store

Tubers being loaded into a ship

BY IMPLEMENTING THESE STEPS, LESS INSECTICIDE FOR VECTOR CONTROL WILL BE NEEDED.

THIS WILL NOT ONLY SAVE YOU UNECESSARY AND COSTLY SPRAYING, IT WILL ASSURE YOU OF HEALTHY, MARKETABLE CROPS EVERY SEASON - AND A HEALTHY RETURN ON YOUR INVESTMENT.

BETTER YIELDS OF QUALITY TUBERS WILL BE THE RESULT.

THIS INCLUDES QUALITY SEED POTATOES FOR LOCAL & EXPORT MARKETS

DISSOLVE to WS of crop being harvested

CUT to potatoes on conveyor, being washed and sorted.

DISSOLVE thru to potatoes being packed.

DISSOLVE thru to graphic:

////MUSIC UP ////

IF YOU NEED MORE INFORMATION OR HAVE ANY QUERIES ON PEST AND DISEASE MANAGEMENT FOR YOUR POTATO CROP, CONTACT YOUR LOCAL INDUSTRY ADVISER, CONSULTANT OR DIAGNOSTIC SERVICE.

////MUSIC OUT///

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THE FIVE STEPS TO A HEALTHY CROP

HEALTHY CROPBUILDING A HEALTHY

VIRUS SYMPTOMS

SOURCE & SPREAD OF VIRUS

VECTOR MANAGEMENT

VECTOR MONITORING

VIRUS MANAGEMENT

STEP 1

STEP 2

STEP 3

STEP 4

STEP 5

Plants with virus symptoms

Show weeds near/in potato crops

Seed & export

Inspector in potato crops

Spraying a crop

Insects & crop monitoring