Archive Article: 1997/10/04

4 October 1997

AS a debut for the British Potato Council (BPC), the outward smoothness of harvesters working on the easy breckland at Knettishall belied intense activity behind the scenes.

Shorn of market control functions, the BPC with a stripped-down staff, is seeking cheaper headquarters as well as closing all but a small Scottish regional office, and is reorganising its internal operations to save further running costs.

BPC chairman David Walker argued that changes being made will allow the council to get the best value-for-money research and make a vast pool of agronomic and potato handling information more accessible to growers through new technology such as the Internet.

The biggest change announced at Potato Harvest 97 was the launch of Rotagrow to run the Sutton Bridge Experimental Unit for the BPC.

This is a joint venture between ADAS, Cambridge University Farm and the Scottish Agricultural College.

Its main remit covers R&D in potato storage and related areas with strong emphasis on getting its findings across to growers and the industry.

Mr Walker said there would be no restriction on the availability of research results from Sutton Bridge to just the partners in Rotagrow and their consultants.

CO-OPERATION of a much more commercial nature was unveiled on the Fenmarc stand where unsuspecting growers could have been forgiven for thinking they had wandered into an Asda fresh produce display.

It was no surprise, however, for Fenmarc grower-members already committing part of their potato production to Fenmarcs cost-plus scheme with the Leeds-based store chain.

They are already undergoing a "culture change", according to Fenmarcs Mark Harrod, leaving behind the market-plus concept where end prices for potatoes fluctuated according to the season with potentially high swings and devastating lows.

Under the deal with Asda, Fenmarc agrees an advance price with growers which gives them a "reasonable margin" and Asda a guaranteed supply of quality potatoes, says Mr Harrod, avoiding the unloved boom or bust cycle.

In its early stages with pre-pack whites and Maris Piper, the contract does not requires a 100% commitment of crop from growers – about a third is being recommended at first.

It is planned, however, to take the concept into niche areas and into early potato production where Fenmarc has marketing deals with Puffin Potatoes in Pembrokeshire.

As the season progresses Fenmarc is due to become Asdas biggest single supplier of potatoes.

Co-operation between supplier and superstore is close enough to give Fenmarc direct access to the instant point-of-sale information on potato sales as they go through checkout tills.

Although details of the Asda deal are not being revealed, there are performance-related clauses which mean Fenmarc has to respond to any fall-off in purchases because of quality difficulties or face losing money.

BLIGHT has been on every ware growers lips during the 1997 season. All except a few, who include, surprisingly, a handful of organic growers.

These are the producers who managed to get their hands on seed from Remarka, a highly blight-resistant variety, which can produce up to 80% bakers – 60% in organic production.

It is accepted by a couple of supermarkets, including Sainsbury, as a baking variety but seed availability is limited and it always sells out quickly, according to David Edwards, of seed producers Gordon & Innes. Other characteristics include a very long dormancy preventing sprouting until at least April, a low fertiliser requirement, and good storage free of soft rotting or blackleg.

POTATO growers arriving at the harvesting demo from Bedfordshire were being greeted with news of the confirmation of brown rot in irrigation water taken from one of the countys rivers draining into the Ouse system.

Confirmation of the diseases appearance in glasshouse tomatoes treated with extracted water came after officials had hoped earlier outbreaks had died out and were unlikely to be repeated.

Although the season for irrigating potatoes has passed, Ministry of Agriculture officials now have to check potato crops in the undisclosed area of the outbreak and consider whether any restrictions need to be imposed before next years planting season.

Brian Ellam, of MAFFs plant health and seeds inspectorate, said growers would be given as much notice as possible of any restrictions so they could make alternative cropping plans, if necessary. He agreed that the outbreaks in England and Holland indicated the bacterial virus appeared to have adapted to the more northern parts of Europe, although the infection is usually associated with warmer countries such as Egypt.

The bacteria finds a host in British waters in the roots of Bittersweet (Solanum dulcamara) which is often found growing on river banks with its roots in the water. MAFF carries out routine testing of many rivers for evidence of the infection. A new European Directive on brown rot due next year will require such testing to be carried out and provide a framework for countries to impose restrictions on growers so plant health can be safeguarded.

NEXT spring UK potato growers and scientists will be able to check claims for a new biological field spray for preventing common scab on potatoes without conventional seed treatment.

The spray, which will be described as a soil conditioner and therefore free of pesticide restrictions, is based on soil microbes. These attack the streptomyces organism which causes scab before it can do any damage to the potato crop. The principle is said to have been proven in Australia where the microbes are isolated and multiplied for Kings Lynn-based Bio-Logic UK.

Soil samples from UK potato fields were sent to Western Australia where Dr Frank McKenna, of the Bio-genetic Laboratory at Murdoch University, isolated microbes antagonist against UK streptomyces.

He is also developing bacterial viruses which can be applied to potatoes and other crops as seed treatments. One of these applied to potatoes with 25% common scab infection reduced this to less than 1% in the field.

The UK product to be launched next spring is, however, based on older technology which has seen a similar product – SC27 – used on 500,000ha (1,235,500 acres) in Australia with a claimed success rate of eliminating 95% of the targeted disease. Under UK conditions, the recommendation is likely to be for at least one or more applications to soil in potato fields at an ingredient cost of up to £80/ha (£32/acre). Legally, it cannot be described as a seed treatment although the importers argue that growers may choose to apply their soil conditioner directly to the seed.

CONDENSATION costs money – as the Scottish grower whose crop went for £5/t stockfeed at a loss of £11,000, while the 45t he had lent to the SAC for a storage experiment sold at £65/t, found out.

The key to controlling condensation is making sure that warm air isnt allowed into the store either when loading out or when normal ventilation is taking place.

SAC developed software for the control system in their experimental store to stop ventilation with outside air when there was a danger of condensation forming on the potatoes.

According to Rod McGovern, of SAC Aberdeen, the system worked sufficiently well to avoid the use of the stores refrigeration system throughout the six months of storage.

The bulk of the crop kept in the growers own ambient air cooled store suffered badly with skin spot which appeared only in small traces in the SAC store. "By reducing moisture, disease is reduced," said Mr McGovern. Sensors attached to potatoes during storage measured any moisture present.

He suggested growers avoid, if possible, opening their main store doors when warm air was likely to blow through.

SEED producer Gordon & Innes is expanding its product range with an electrostatic sprayer claimed to give better coverage in potato crops than any existing conventional or air-assisted sprayers.

The same nozzles which apply an electrical charge to the chemical being used are also being adapted for use on treater tables for potatoes going into or out of store.

Commercial director Alistair Roy decided to import the nozzles and other components for electrostatic spraying after seeing the system in the USA. A particular benefit for UK potato growers, he reasoned, would be the ability to cut the conventional spray requirement of 300 litres/ha of water to just 30 litres/ha.

The improved, all-over coverage from the electrostatic spraying should also allow chemical rates to be reduced without loss of control. Some evaluation work has been carried out on carrots and cereals.

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