Looking ahead to this year's potato growing season

Eight of the 12 months of the year were warmer than average, and some parts of the UK received over a third more rainfall than normal. A very welcome late season heatwave in September abruptly ended with Scotland’s two wettest days on record, on October 6 and 7, and the number of named storms last year must have challenged the name givers almost as much as those watching the elements play havoc with their crops in the ground.

The cool spells of March and late April delayed the start of potato planting, but European farmers were arguably more adversely affected by the erratic weather patterns. Planting dates were three weeks later than average, and there were sharp increases in late blight and virus, culminating in a miserable autumn making harvesting difficult or impossible.

Costs of production for seed crops are now over £6,500/Ha before rent

Scotland’s potato farmers felt the brunt when it came to lifting too. October 2023 was eastern Scotland’s wettest on record by a large margin from the closest previous record in 1836, and two Met Office red weather warnings. A few crops couldn’t be harvested at the back end of the year between the torrential rainfall and soft ground.

On the continent, many had hoped to salvage some crops early this year, but recent sub-zero temperatures will undoubtedly have had a further detrimental effect on potato crops that weren’t harvested. The soil is now saturated to the extent that it will not be until early spring before it will support the weight of harvesting equipment.

Recent reports highlight a significant loss in the potato crop, with an estimated 11,000 hectares written off and a minimum of 650,000 tonnes lost, either in fields or post-harvest.

The 2023 European potato processing crop production is comparable with 2021 but processing needs have strongly risen. Continental processors need an estimated additional two million tonnes of potatoes compared to two years ago. Processors will therefore support the bottom end of the ware free buy market both on the continent and in Great Britain as the 2023 storage campaign draws to a close.

A shortfall in continental seed is pushing prices beyond 800 euros per tonne.

The cost of production is becoming scary and requires scrutiny. We will need to see urgent and attitudinal changes within the potato industry across many fronts if businesses are to remain sustainable, and that’s not just for the environment.

Costs of production for seed crops are now over £6,500/ha before rent. On a typical potato-producing unit, power and machinery depreciation costs alone represent over £1,800/ha. The cost of input seed varies between £1,000/ha for ware and £2,000/ha on seed crops. Furthermore, under the current certification system, there is no guarantee of freedom from primary virus.

Eric Anderson, Senior Agronomist at Scottish Agronomy

The capital cost of boxes is now over £500/ha, just one example of the high capital costs associated with potato production, but even this cost is dwarfed by the expense associated with investment in new buildings and grading equipment.

Therefore, surely efficiency is the key going forward, not scale.

Controlling disease is also at the top of minds for potato producers. An aggressive blight genotype resistant to certain fungicides is now widespread in The Netherlands, Belgium, and north-east Germany. Fortunately, it has not yet been attributed to any late blight outbreaks here in Great Britain, largely through the continued use of Mancozeb.

First registered in 1948 and used without issues since then, after 76 years of use,the GB decision announced on January 9 to propose withdrawal of Mancozeb was hugely significant. Not only does it pose a challenge to British potato growers who will need to take extra care when planning late blight control strategies, but the way legislation was enacted in this case sets a dangerous precedent.

It’s interesting to see how growers on the continent are reacting to blight. Dutch growers reported the worst blight epidemic for 30 years and after the disease was found in crops, many producers in the Low Countries broke every rule in the resistance management manual with CAA and oxathiapiprolin use. In contrast, Denmark experienced higher blight pressure and had access to a narrower choice of chemistry, but late blight was comparatively well controlled by following best practice advice to alternate and mix modes of action throughout the season.

The very high incidence of foliar and tuber blight in continental seed and a likely shortfall in British seed this year means there is a real risk of importing latent infection. Anti-resistance management strategies will be a key component of Scottish Agronomy advice this year to avoid it getting a foothold. The information generated from our trial sites and from collaborations on members’ farms, for which we are very grateful, comes into its own at times like this to guide the decision-making process.

Decisions will get harder with less predictable weather patterns and the unknowns around chemistry many have traditionally relied on, as well as increasing costs of production. We cannot move ahead by constantly looking in a rearview mirror, though, so we need to use the information we have – from different ways to manage potato crops to the known potential disease threats from across the North Sea – to make the best decisions based on what we do know as we approach a new potato growing season.