Sharp rise in ware potatoes failing virus inspections

Department inspections have resulted in an increased area of ware potatoes failing while seed potato disease levels remain unchanged and retain their typical high health status.

Crops that express high levels of virus are compulsorily destroyed by the Scottish Government department in a bid to slow the spread of the disease to other fields.

So far in 2024, 64.4 hectares of ware potato crop have been destroyed, which is double the 32.6 hectares destroyed in all of 2023. While there is growing concern about increased levels of virus in potato crops, the jump in area is also accounted for through larger fields failing. When the virus is found in one a crop, the entire field must be destroyed to limit the spread.

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There has been a sharp rise in ware potato crops failing inspection

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To date, potato leaf roll virus appears to be the dominant virus in Scottish potato seed crops this season, but seed crop inspections are still ongoing. If a grower has their field destroyed, there is no compensation from the government, and most often the tubers are not of a commercial size to harvest. Furthermore, the crop is often mechanically destroyed, which leaves tubers in the ground that can be a source of the virus the following year.

The loss of chemical sprays and desiccation options have been partly blamed for the presence of the virus, with warmer winters also contributing to disease overwintering. However, these diseases offer no danger to consumers which are still demanding high volumes of potatoes. Currently the spot price for Maris Piper is close to £500/t as old season stocks run low.

A Scottish Government spokesperson told the Scottish farmer: “The Scottish Government is committed to working in partnership with seed and ware potato growers to maintain the world-class reputation of Scottish seed potatoes, based on the quality and health of the product.

“Growers play a vital role in minimising the risk and spread of pests and diseases, and in enabling swift action to be taken when necessary to suppress the transmission of viruses affecting potato crops. This decisiveness is vital to the Scottish potato industry and improves market conditions.

“The extent of virus infection in this year’s seed crop is yet to fully emerge but early indications are that levels are comparable to the 2023 season.

“We recognise this is a challenging reality for farmers and appreciate their efforts to prevent the spread of crop viruses and protect Scotland’s high health status.”

Scott Walker chief executive of GB Potatoes said: “Scotland's potato production is renowned for its excellent plant health standards, and only produces seed potatoes of high health status. To maintain this reputation, the industry must address the threat of aphid-borne virus and changes in virus profiles, such as the increasing prevalence of leaf roll. Comprehensive guides—four steps for ware growers and six steps for seed growers—have been developed to enhance awareness and control measures within the industry.

“Historically, the ratio of seed to ware potato production was higher. Today, there is a greater proportion of ware production compared to seed production. Most of the risk in the current control measures is being borne by ware growers, who must destroy their crop if an inspector deems that the virus present is too high and poses a risk of spreading to other potato crops. This represents a significant financial loss to a grower, potentially jeopardising the viability of their businesses.

“All growers both ware and seed understand the necessity to address aphid-borne virus and recognise that a collaborative approach between industry and government is essential. With the chemical options available to growers continually decreasing a risk to benefit approach needs to be taken on approval and renewals. We must ensure that the control measures in place truly protect the crop and find ways to ensure that both ware and seed crops can thrive successfully. A thorough review of existing measures is necessary to ensure that we have effective preventive and corrective actions in place, based on the latest scientific understanding and the current threats.”