The technical challenges of coping with a reduced pesticide armoury were high on the agenda at a recent Potato Council Yorkshire Potato Day.

If you rent land, don’t saddle yourself with soil-borne threats. Techniculture’s Neil Pratt told growers at the event they needed to plan carefully and gather as much information about rented land as possible.

“Here in Yorkshire much of the crop is on rented land, but you don’t need to go in blind. Risk management is essential, as the cost of failure is now devastating.”

Tackling potato cyst nematode had become increasingly hard for those on the Yorkshire Wolds. “It’s largely come about as a result of short potato rotations. If you look at the advice given in the past, making decisions based on short-term yield responses, rather than long-term population control, you’ll understand why we’ve ended up with the mess we have.”

Growers should seriously question the economics of renting infested land, and clean land was likely to be offered at a premium, which might be well worth paying. “PCN is going to be increasingly hard and expensive to deal with. Good hygiene with machinery and seed is imperative; if you have clean land, keep it clean.”

Diagnostic tests gave a useful indication of other diseases, most notably black dot, advised Mr Pratt. Short rotations again had implications for the disease. Growers should pay attention to soil conditions at planting, manage nitrogen inputs carefully to quickly achieve marketable yield, and try not to delay harvest once skins had set.

“We have challenging soil conditions this year; just be patient and plant when soils are right. If the crop is limping along, the chances are it will catch a cold.”

Directive needs direction

All potato crops will be affected to some extent when the new potato cyst nematode (PCN) directive comes into force in July 2010. A DEFRA consultation on the directive is due to begin this month (March), Central Science Laboratory’s’ Sue Hockland told growers.

“I’d advise all growers to look out for the consultation and assess its impact. It will affect some more than others,” she noted.

A key part of the consultation DEFRA wishes to consider will be the risk of spreading PCN. The aim of the directive is to harmonise standards across Europe, which means a harmonised sampling procedure and tighter definitions to ensure seed crops are free from PCN.

“All seed land will be subject to statutory tests and assessments will also be required on land where crops are grown in rotation with potatoes and then transplanted. Requirements on farm-saved seed will be part of the consultation. If seed is used on the same holding, without increasing the spread of PCN, the directive provides that land won’t need statutory sampling.”

However, a strict approach on this issue would affect businesses where farm-saved seed is moved between holdings. A new change is to include an annual survey of 0.5% of ware land and for an officially approved control programme to be implemented on known infested fields.

Pesticide pledge

UK Agriculture must remain united in its fight to minimise the impact of the pesticides directive, JSR Farms’ director Philip Huxtable told growers. Lobbying by the whole industry had helped reduce the loss of pesticides under Directive 91/414 from a potential 85% to the current 15-20%.

“But we face major challenges under the Water Framework Directive, we have lost isproturon (IPU) and are likely to lose metaldehyde and chlortoluron. A current theme throughout the negotiations is that companies would just find a new product to replace any that are lost, but pulling rabbits out of the hat is not that simple.”

He said it had been an eye-opening experience for him representing the UK grower in Brussels and Strasbourg. “It’s only when you go there you realise the problems the industry faces. The Green Party has established itself in Strasbourg and has big changes planned for agriculture.”

Minimising the impact of these would be a “shared responsibility”, according to other speakers at the event. A recurring theme was that growers should not rely on others to interpret legislation, and that demonstrating best practice was the best route for the industry to manage the increasing burden of regulation.