[rookie1]

Hi Spudonauts - just curious ... is it a bad idea to let born again tatties grow? I thought I'd cleared all of last year's, but it appears there were some tenacious little tatties lurking in the soil and they've now started flourishing and putting on top growth. Should I dig them up, or give them a second chance. Many thanks.

[DD.]

Clear them out. They could be harbouring nasties such as blight.

Plot hygiene is paramount!

[pdblake]

In the garden I let them get on with it, but up at the plot I oik them out. In the well hedged and sheltered garden they're my problem, on the plot they could, potentially, be everyone elses.

[simonwatson]

Last year was a bad year for blight and overwintered spuds are the one place that blight can survive to begin the destruction anew this year.

[seaside]

I am fully aware of the obvious communal hygiene worry, and duly go along with it, and certainly wouldn't dream of leaving a volunteer that I know had suffered the previous year.. But what is the science behind this and in today's cynical world headed up by the likes of Monsanto, is there a modicum of seed pot growers influence in there where only the big operators and growers can be trusted to pass on supposed healthy tubers for the next season ?
Every field, plot and worked vegetable garden in the country probably has volunteer potatoes and the now vacant plot next door to me has many sprouting after last year having a huge blighted crop.
I ask, because I notice uncertified seed potatoes seem to be The cardinal sin of vegetable growers, yet in my observation round and about, only show signs of blight when all the other bought in seed potatoes show signs of the dreaded plague as well... they have certainly never shown  "herald" symptoms before the rest of the plants.

My other neighbour also grew potatoes last year, used a blight resistant variety, and was one of the few that didn't suffer at all amazingly. Does this mean his volunteers as well should be pulled ? Given the Darwin thing I would have initially thought his volunteers this year should be hailed as super spuds ?

[arugula]

But what is the science behind this

It is that certified seed potatoes are just that and by using them, you can help to avoid introducing disease and pests. If you were to keep reusing your own saved seed, even if your crop wasn't blighted, you'd be running the risk of disease appearing.

[azubah]

I use a crop rotation system, so the volunteer spuds come up in amongst the next crop and so are a nuisance.
I usually try to get them out.

[seaside]

But what is the science behind this

It is that certified seed potatoes are just that and by using them, you can help to avoid introducing disease and pests. If you were to keep reusing your own saved seed, even if your crop wasn't blighted, you'd be running the risk of disease appearing.

But this is my question. Surely other diseases are not relevant as the same argument could be made for all seeds as the EU were ludicrously trying to do just recently... a move that many people on here have signed a petition against. Talking blight only here, which given it's almost epidemic proportions, is the only disease and reason that is used to validate the commonly held view on volunteer potatoes, when nature throws up potatoes that succeed in avoiding the effect of the spores ... ie they have actual proven in the field immunity while all around them perished, then surely these potatoes are as good a bet as any from some mass producer. And let's be honest the certified potatoes have given next to no immunity and still seem to take a tumble with alarming regularity these days. Are they breeding potato softees in some sterile conditions that are in reality hopeless when blight comes a knocking ? If the logic were followed through, surely all potatoes that are not considered blight resistant should be withheld in today's climate. Where is the actual methodology and science ? Does anyone know just what methods the seed potato producers use  ? All I want is to see a convincing argument and I would be delighted to find the methodology on it to put me right, but try as I may, I can't find any.
I noted last year everyone in the industry and their dog blamed the allotment holders for yet another nationwide blight. How can they do that when 99% of potatoes were supplied by them ? Just what criteria need to be met to give the certification ? Does anyone know where that information can be accessed ?

Sorry to harp on 

[arugula]

But what is the science behind this

It is that certified seed potatoes are just that and by using them, you can help to avoid introducing disease and pests. If you were to keep reusing your own saved seed, even if your crop wasn't blighted, you'd be running the risk of disease appearing.

But this is my question.

They're certified, meaning they have to guarantee to meet a certain standard.

You could have a read of this:

http://varieties.potato.org.uk/classification.php

and this:

https://www.gov.uk/the-seed-potato-classification-scheme

[Yorkie]

Seaside, you are confusing two separate issues in your haste to condemn anything regulated as inherently evil.

Certified seed potatoes are certified free from viruses.  You cannot tell a diseased tuber at planting.

One of our members is a professional potato grower, based in Scotland where the aphids (disease transmitters) are few and far between.  He was given a seed tuber by an old friend, with promises of it being a really good variety.  Luckily for him, he grew it in an isolated container away from his professional crop.  It was heavily infected with a virus and had to be destroyed.  Had he planted it near his professional crop, not only would he have lost them, but he'd have risked his livelihood i.e. his licence.

Blight is an air-borne fungal disease.  It overwinters in plant tissue, e.g. volunteer spuds.  When conditions are suitable (Smith periods), it can be reactivated from the volunteer material, thus reintroducing the blight spores to the localised environment where they might otherwise not have arrived, and risking contamination of your allotment site and surroundings.

That is why plant hygiene is so important.

[seaside]

When I say volunteer potatoes, I really mean the saving of one's own blight free potatoes one has verified oneself, as is suggested by organic gardeners when using early potatoes saved from one's own crop to replant as Christmas potatoes. I fail to see why potatoes are any different than any other seed saving... all crops have pests and diseases.
No one in their right mind is going to plant potatoes that take up a lot of room and time only for them to fail. I'm merely questioning the science and whether the official certification methods in place are working. Just what makes potatoes so special over any other crop ?  Recent regular blight disasters show the present system is patently failing  and the introduction of Sarpo potatoes ( from Scotland  ) has done more against blight than any of these certification measures.

It seems to me very small "pure" stocks are dominating for some reason, and I just can't see that being scientifically a good idea... and with that in mind, thanks for your link Arugula, and I had read that ...
This quote worries me as it goes against all known Darwinian thoughts. When blight strikes, everyone has the same derived stock ... a recipe for disaster if ever there was one. Still, ho hum :-

Commercial multiplication of nuclear stocks is done, under strict official control, by officially approved laboratories. Micro-plants are then planted either in a pest-free medium, normally in a protective environment, to produce mini-tubers (Pre-basicTC), or in the field to produce first generation seed tubers (Pre-basic1). These initial tubers are multiplied by specialist, officially approved Pre-basic producers for a limited number of years before being used to produce the Basic or Certified seed that is marketed to domestic and export markets. Classification of Pre-basic and Basic seed potatoes in Britain is based on limited generations within each class and seed potatoes intended for export will, typically, have been multiplied in the field for only 3 – 6 generations.

[Yorkie]

I fail to see why potatoes are any different than any other seed saving... all crops have pests and diseases.

Potatoes are a staple crop, particularly in parts of Europe.  Viral disease is currently highly controlled, and the sanctions for selling or imported non-certified seed tubers are huge because of the huge ramifications of allowing disease to spread unchecked.  I have seen no reports of crops being wiped out by viruses - evidence that the control programme is working.  I suppose it's like the polo disease - practically eradicated through preventative measures.  If something is working, you don't decide to stop it and risk unstoppable consequences.

I'm merely questioning the science and whether the official certification methods in place are working. Just what makes potatoes so special over any other crop ? Recent regular blight disasters show the present system is patently failing  and the introduction of Sarpo potatoes ( from Scotland  ) has done more against blight than any of these certification measures.

You are still missing the point.

Certification is irrelevant to blight.  It relates to viruses.  Your assertion that fungal blight = evidence that viral prevention doesn't work, is illogical.

Blight is fought through other methods, including the more resistant varieties.  Or spraying.  Or preventative methods such as removing the risk of re-infection of diseased plant material

[Nikkithefoot]

Certification is irrelevant to blight.  It relates to viruses.  Your assertion that fungal blight = evidence that viral prevention doesn't work, is illogical.

Blight is fought through other methods, including the more resistant varieties.  Or spraying.  Or preventative methods such as removing the risk of re-infection of diseased plant material

At the risk of being shot down, and merely being devils advocate, what you are saying is that certified potatoes are certified against viruses only, but COULD possibly still harbour blight spores if they had become infected during the previous season, especially as there does not appear to be anyway of visually checking the potatoes?

I do however accept that blight is much less prevalent in Scotland where many seed potatoes are produced, and therefore the risk of transferring blight spores in this way is much less of a risk.

[seaside]

Potatoes are a staple crop, particularly in parts of Europe.  Viral disease is currently highly controlled, and the sanctions for selling or imported non-certified seed tubers are huge because of the huge ramifications of allowing disease to spread unchecked.  I have seen no reports of crops being wiped out by viruses - evidence that the control programme is working. 

With respect Yorkie, this is the same line put out by the EU about seeds of all big crops under some geo strategic food security issue. Centralised stock rearing controlled by a few big players doesn't sound very resilient to me in the long run, let alone it encouraging seed potato prices to go through the roof.

I did however recently listen to a BBC radio article on the agriculture authorities and farms that commission, research, grow and supply the various grass seeds for the farming industry. Now that project made excellent sense, and there's no bigger staple food in this country than grass.
A touchy subject I feel, seed potatoes, with not a small amount of religious zeal down on our allotment site from the odd person or two. And the emotive weight behind the argument unmistakably hangs on the coat tails of blight, regardless of the viral reasoning in the laboratories. It's the fear of blight that gives the status quo credence.

[Aunt Sally]

We are quite a long way from the original posters question:

Hi Spudonauts - just curious ... is it a bad idea to let born again tatties grow? I thought I'd cleared all of last year's, but it appears there were some tenacious little tatties lurking in the soil and they've now started flourishing and putting on top growth. Should I dig them up, or give them a second chance. Many thanks.

To sum up:

Yes it is a bad idea to allow volunteers to grow on.  They may have been infected with blight from last years high blight infections and they may be infected with voirus from last years aphid explosion.

So I remove all volunteer plants.  (I also choose NOT to grow anything but fresh seed potatoes each year but that was not part of the OP's question).

Topic locked.