Tattie Roguing – The Best Summer Job
Quality Control in Potatoes
How do you know that the variety of potato you buy in a supermarket, or from us is actually what the label states?
School's out! Like many parents with teenagers we hope that our kids will get a job to get them out of the house! They could be waiting staff or get a job in a shop, but our older two have decided on a summer tattie rouging.
Quality control in a crop is a cycle, and one step is dependant on the one prior to it, and there is no one point where that cycle starts and ends. Tattie Rouging involves walking, walking and more walking. They are over 20,000 steps daily going up and down all the drills finding rots and also any "rouge" plants - ie a plant that shouldn't be there. That could be weeds, or some crop from the previous year or "rogue" potatoes that are not the correct variety.
Identifying the plants sounds easy, but most people do a tattie rouging course in Aberdeen. Passing that means that you can confidently identify at least 20 varieties of potatoes but their stems and flowers as well as many diseases.
So our 17-year old clutching his new driver's licence in one hand and his tattie rouging certificate in the other found a job with colleagues of ours for the summer with his 16 year old sister following behind. As many will have noticed we are currently on "normal" for weather for July - rain and more rain, however their tans / weather beaten looks are coming on!
They are working on a farm which supplies mainly seed potatoes like us, and so their work in taking out virus so the seed next year is high quality, is a crucial cog in the wheel.
The rogues can be plants that grow as weeds from a previous crop, or from the wrong variety planted along with the intended crop seeds, explains Dr John Kerr, head of the potato branch at the government body Science and Advice for Scottish Agriculture.
Or they can be plants with virus or blackleg, or plants that are not "true-to-type", meaning they have the wrong morphology and are therefore too tall or deformed in another way, he adds.
Roguing can be done from a few weeks after the potato plants emerge until the crop is harvested, but it usually is done in the days before an official seed inspection, which in Scotland is during July.
All seed crops, like ours, are inspected twice before being certified by government inspectors.
Roguing can allow the crop to pass inspection, making it worth perhaps four times the value of a ware or stock feed crop - which is what it would become if it were to fail, Dr Kerr explains.
There’s quite a range of different viruses that affect potatoes, the main ones are Leaf Roll Virus, Mosaic virus, black leg (bacteria).
But the commonality between them is that they tend to be transmitted by aphids.
In Scotland – particularly up the east coast – we have fewer of these aphids than in other parts of the UK.
That puts us at a climactic advantage and allows us to supply some of the world’s best quality seed potatoes – in Scotland and England but also globally.
However, our climate doesn’t prevent all chance of disease. As such, roguers are needed to ensure that crops pass inspection at the highest grade possible.
Parts of Scotland grow seed potatoes at the very highest grade. We’re talking about 0.1% of plants infected or in some cases even one infected plant can result in a downgrade.
And so roguing, which is a very skilled job, really does add value. The countries which buy that seed – Egypt, Morocco, Israel, Thailand, Brazil and many other places – do so because they know the virus health of Scottish potatoes is amongst the highest in the world.
When you buy your UK Certified Seed Potatoes, or indeed your potatoes to eat from a supermarket, you can be assured that the variety that is on the label is exactly what the potatoes are.
Background information taken from
Unsung heroes of Scotland's Potato Industry - BBC
Tattie roguers and the draw of Scotland's potato fields - The National
