Potatoes rank as the fourth most important food crop in the world. They are a recognised wholesome food and their condition is subject to good agricultural management.

Unfortunately, potato crops are prone to an increasing number of fungal, bacterial and viral diseases, some of which cause little damage, while others can cause serious damage leading to quality reduction and yield loss.

Accurate and timely disease diagnosis is vital, as markets require high quality products and growers remain under pressure to reduce costs and maintain profitability. Some potato diseases can be diagnosed visually. However this task is not always straightforward. In some cases, laboratory testing is necessary to confirm suspicious symptoms, but results can take days or even weeks to come back.

At the Defra Executive Agency, Central Science Laboratory (CSL) in York advances have been made in the development of rapid, on-site diagnostic kits, which have been trademarked as Pocket Diagnostic®. These handy, portable kits enable accurate and speedy diagnosis of disease problems in the field and can be used with little or no equipment or training. They utilise a similar technology to that of home pregnancy tests and are robust and simple to use. The kits provide easily interpretable results in minutes, giving the grower confidence to make crop protection decisions on the spot, so there is no need to wait for laboratory tests.

The kits contain everything required to extract and test symptomatic plant material in the field. They are available for the potato viruses PVY, PVX, PVA, PVS and PVV, which are important diseases for seed potato growers and are now used routinely by UK and EU Plant Health Inspectors as additional tools for maintaining potato seed health. UK growers have also started to see the benefits of the kits, for example, when seed is entered for certification and growers are unsure of suspicious symptoms in their crop, by using the Pocket Diagnostic® kits, they can have peace of mind from viruses that could fail or downgrade their crop at inspection.

Neil Pratt, agronomist at JSR Farming Group (UK), which operates and manages land extensively throughout Yorkshire and Lincolnshire and amongst other produce, grows a substantial acreage of potatoes for seed, said: “I am happy with the potato virus testing kits, they are an invaluable resource to seed potato growers.”

All five potato virus test kits currently available from the Pocket Diagnostic® range have been evaluated by the Defra Plant Health and Seeds Inspectorate, laboratory staff and inspectors at the Scottish Agricultural Sciences Agency, and their equivalent organisations in both the Netherlands and Denmark. More recently a kit to detect Ralstonia solanacearum (the bacterium that causes brown rot of potato tubers and bacterial wilt of potato plants) has been evaluated and approved by the US department of agriculture, animal plant health inspection service, plant protection and quarantine (USDA, APHIS, PPQ).

The kits are utilised worldwide. Phil Jones, a senior researcher at Rothamsted Research (UK) took them on a field trip to Bolivia. He said: “They are ideal for the kind of work and situations associated with my research. I like the small, lightweight packages with everything included. These kits are very useful in underdeveloped countries and remote areas, as they do not require the user to have access to a laboratory. It's very satisfying to see your symptom diagnosis confirmed on the spot.”

Also available in the potato range is a kit for Tomato Spotted Wilt Virus, which affects potato crops in Europe, Asia, Africa, North and South America and Australasia.

The Pocket Diagnostic® range has expanded to provide tests for 16 different pathogens affecting arable, horticultural and ornamental crops. Additional kits for the detection of Clavibacter michiganensis subsp. sepedonicus (the bacterium that causes ring rot of potato), Erwinia amylovora (the bacterium that causes fire blight of potato) and Phytophthora infestans (the fungus that causes late blight of potato) are in development at the present time.

To ensure the highest quality for all products, CSL announced that all Pocket Diagnostic® kits are developed and manufactured under controlled environment conditions. To achieve this, the Pocket Diagnostic® team has recently moved into a new purpose built £500,000 facility and are hoping to soon attain ISO 9000:2000 series accreditation.

CSL works closely with the potato industry at local, national and international levels to meet the needs of the global potato industry. A committed group of individuals responsible for managing Pocket Diagnostic® sales, customer service, manufacture and new product development help meet this requirement.

Further info and contact details are available at the website: www.pocketdiagnostic.com.

POTATO TRADER GETS INDEXED

Alexander Harley Seeds Ltd (AHS), established in 1947, is now the UK's largest potato breeder. Within its group of companies AHS handles all aspects of the potato life cycle, to ISO 9000 standards. The operation ranges from breeding mini-tubers, through seed potatoes to ware.

Traditionally, estimating the tonnage of seed potatoes that a farmer requires has been a tricky business, as during the season size and weight differences can lead to a variation of up to 40 per cent in the number of seed potatoes per tonne.

In the last few years AHS has been innovative within the sector, trading its potatoes in thousands rather than by the tonne. This enables its customers to be far more specific and buy precisely the right quantity of seeds to plant a given area, thereby maximising the harvest while minimising costs.

To manage this, AHS needed a potato trading system that could handle both tonnes and thousands and worked in conjunction with INDEX, which has developed and implemented the second generation of such a system.

AHS has had a close working relationship with INDEX since the early 1980s, to implement and support its core business systems. The new system enables AHS to constantly re-balance its stock as the season progresses, allowing customer-specific trading ñ in thousands or tonnes of potatoes.

The latest release enables AHS to buy in potatoes from third party suppliers, not just from its own farms. Doug Harley, grandson of the company founder, estimates that in the market in general 90 per cent of potatoes are still traded by the tonne, but the vast majority of existing AHS customers (up to 90 per cent) are realising the benefits of buying in thousands, and reaping the economic benefits.

The system runs on IBM Netfinity hardware with connectivity to all the subsidiary companies within the AHS group by leased line or ISDN link. The potato trading system links into the existing Amazon core business system.

The system handles the full range of sales order processing including bulk and call-off orders and provides a highly flexible invoicing structure. The AHS group has nine different invoicing layouts, according to what is being sold and to whom, which are automatically linked to the order type.

AHS said it has been able to tighten its stock control by implementing the system, and benefited from faster and more accurate processing of its core business information.

One of the unforeseen benefits is the ability of staff from any of the AHS divisions to work in its sister companies.

Implementation of the system was very smooth. There was just over one month between agreeing the specification and the system being implemented. Harley said: “We just told INDEX what we wanted, in some detail, and they delivered it.”

The system, which consolidates the business from all the potato related operations within the extensive AHS group, is enabling AHS to expand, improve margins, and to continually meet its customers' needs.

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