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A fully-integrated approach to PCN control

To find sustainable ways of controlling potato cyst nematode and ensuring continuity of supply of quality spuds will require thinking outside the box. ADAM CLARKE explores a solution that showed real potential in recent on-farm trials.

To protect crop yield where potato cyst nematode populations are high, growers have long relied on chemical control using soil fumigants such as metam sodium and granular nematicides such as oxamyl (Vydate) and fosthiazate (Nemathorin). With nematicides under continued regulatory scrutiny, the current strategy for PCN management could be on shaky ground and some believe that a serious rethink is required to ensure that potato production can continue at current levels.

Peter Blaylock, agronomist with Yorkshire grower and packer E. Park & Sons, says the industry is at a crossroads where it must make fundamental changes to tackle the PCN issue. ‘Growers have had their heyday of high prices and tight rotations and that’s why we are where we are with diseases, blackgrass in cereals and PCN in potatoes,’ he says. ‘You can’t just keep doing the same thing and expect a different result.’

With its links to supermarkets, the Doncaster-based company is more aware than most of the pressure coming from retailers and consumers to find more sustainable methods of production, using fewer chemical inputs. To work towards this aim, Mr Blaylock set up trials looking at various alternative PCN control methods, including trap cropping and biofumigation. While neither are novel methods, there was a twist.

His vision is to include a ‘remedial fallow’ year during the potato rotation, where a trap crop using a variety resistant to both PCN species is established following an application of nematicide, slashing the PCN population. Within the same year, it may then be possible to incorporate a biofumigation crop such oil radish and mustard to add to PCN control. These species are also proven to provide suppression of other pests such as beet cyst nematode and, like other cover crops, can offer soil conditioning benefits.

Read the full article in our Nov/Dec edition

Why organic producers need robust varieties

Produce World agronomist Caroline Williams has been working with Joe Rolfe, general manager at Organic vegetable producer Taylorgrown Ltd, to develop a selection of potato varieties for Waitrose. We caught up with them both in trial plots on the Houghton estate in Norfolk.

Joe Rolfe is determined to prove that quality organic potato crops can be produced economically and sustainably at Houghton Hall, the country seat of 18th Century prime minister Sir Robert Walpole and current home to the seventh Marquess of Cholmondley. Mr Rolfe joined Taylorgrown at the Home Farm 10 years ago where he oversees production of organic carrots, onions, beet root and potatoes.

Taylorgrown was set up in 2005 in partnership with the Burgess family and is a wholly-owned subsidiary of the Produce World Group, hence Caroline Williams’ involvement. She is based at the former Solanum packhouse at Sutton Bridge in Lincolnshire where she has worked for several years on the Waitrose account. This season she has been helping Joe Rolfe with variety and trickle irrigation trials.

‘Potatoes are probably one of the easier organic crops to grow in terms of weed control, as opposed to carrots and onions where we spend a lot of money on hand labour,’ said Mr Rolfe. ‘We don’t have to do that on potatoes because we can burn them off and they will recover.

‘Crop health is achieved through long rotations, by planting seed into healthy soils and by growing potatoes at the right stage in the rotation, following on from a nitrogen fixing crop rather than carrots, for example. We’re trying to produce a plant that will protect itself so that we’ve not had to rely on copper. The mind set of the conventional grower is that you get blight and you spray it with something, but we needed to get away from that by using the right varieties that have some resistance built into them.’

‘With the loss of copper Joe is trying to push expectations and see it as an opportunity rather than just giving up on blight,’ said Caroline Williams. ‘A lot of organic growers just accept that they are going to get half the yield but we want to help challenge that. By identifying good disease resistance in organic varieties we could also cut down on blight sprays used by conventional growers.’

Keeping infection to a minimum was one reason for trying out trickle irrigation at Houghton, she explained. ‘At Produce World we have been big fans of trickle and we thought that keeping the canopy dry would help. We still got some blight so the trial hasn’t been a complete success but next year we’ll also be looking at seed spacing and planting densities so that we don’t create a microclimate which favours the disease.’

Read the full article in our Nov/Dec edition

Different markets, different priorities

Rufus Pilgrim’s day job is managing the fresh division of Yorkshire potato supplier R. S. Cockerill Ltd. The company is also involved in processing and for both sectors matching customers’ value expectations has been an increasingly important issue. A Nuffield Scholarship gave him the opportunity to see how other nations cope with such challenges.

The objective of my Nuffield Scholarship was to gain some understanding of the factors that influence our potato market, and see what could be done to combat the volatility, uncertainty and short termism that has blighted the UK industry. To do this I visited Central and Northern Europe, Kenya, South Africa, Canada and the United States.

The first thing to understand is the dynamic nature and sophistication of our own supply chain compared with others. UK consumers expect quality and provenance while, at the same time, they are very value conscious. Domestic demand for frozen potato products exceeds supply, resulting in us importing 600,000 tonnes each year, predominantly from Northern Europe.

For some regions the challenges are more basic. In South Africa, for example, the only buying criterion for many is cost. Potatoes compete with maize to be the daily carbohydrate of choice with purchasing decisions based around whatever is cheapest on the day. It’s a case of quantity over quality that has seen a proliferation in the use of high-yielding, low dry matter varieties over the more traditional flavoursome ones. For others the challenge is to establish a supply chain.

The Kenyan Government’s focus is on achieving food and nutritional security for a growing population and, importantly, a fair and secure route to market for potato producers. Working with European seed houses and development organisations is part of a plan to establish a robust potato supply chain. This role is performed by the National Potato Council of Kenya, but in other potato producing regions the involvement of professional trade associations extends to gathering and disseminating market intelligence.

Acquiring quality information for effective decision making is a challenge the world over. On a local scale it is achievable to a degree, for example, in the well-regulated provincial wholesale markets of South Africa, where a government inspection service scores individual loads for quality. This tightly controlled physical market allows Potatoes South Africa to publish national prices within a few hours of the market closing each day.

In North America, the United Potato Growers of America, a federated co-operative which represents the state potato boards, meets monthly to review demand forecasts and compare them with remaining stock levels before sharing their findings with grower members. Both of these examples represent a level of intervention more than we are used to.

Read the full article in our Nov/Dec edition

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