Amateur potato growers blamed for late blight.

[peter]

Article quoted from Metro Newspaper and link to actual article appended.

Army of amateur potato growers 'produces worst crop in 35 years'
Many people think they are doing their bit for the planet and even saving money by growing their own vegetables but some could be doing more harm than good.
Britain's grow-your-own army has been blamed for helping to spread the killer potato disease known as 'late blight' which has resulted in the worst crop in 35 years.Unaware of the signs of danger, the 'allotment amateurs' have let their spuds grow unchecked allowing the airborne infection to be transferred to commercial fields, food experts say.
'People should be encouraged to grown their own vegetables to learn about the origins of their food,' Potato Council chairman Allan Stevenson told trade journal The Grocer.
'But the blight risk is real and it would be preferable if people bought healthy potatoes from their retailer rather than grow their own.'
The spread of the disease and one of the wettest summers on record has helped push the wholesale price of potatoes up by 61 per cent in the last year.
While the full burden of the price rise will not be passed on to the customer, the cost of spuds, chips and crisps is set to soar this winter.
The Potato Council has produced a blight fact sheet and other guidance and advice on growing the crop in a bid to educate Britain's 330,000 allotment holders and gardeners.

Read more & comments at Original Source in: Metro Newspaper

[Tony Hague]

So The Grocer and BPC blame amateurs for trying to grow their own potatoes. eh ? Presumably next week turkeys will be voting to cancel Christmas.

Nothing to do with the huge number of tubers left in the ground by commercial grower's mechanical harvesters and allowed to overwinter (along with any blight on them) and grow as volunteers next year then ?

And with the withdrawl of Dithane 945, what do they expect amateurs to use against blight ? Harsh language ?

Not guilty here anyway; my potatoes are usually got by the early blight, so never get a chance to be affected by late blight

[Kleftiwallah]

This Tony agrees with that Tony 100%.

Cheers, Tony.

[farmer jon]

part of this article appeared in todays daily mail & what they were hinting at & rightly so in my opinion is that a lot of amateur growers cannot recognise the symptoms of blight on their potatoes let alone take steps against it. the gardening presenters and the magazine writers need to start educating people about blight & other major veg diseases.
on our local allotment we had people whose potatoes were badly affected by blight to the extent that the tops had collapsed & the tell tale putrid smell was hanging in the air ,yet they were in total denial that they had blight.thanks to the EU & others we now have no dithane 945 & are left only with bordeaux powder which is much less effective. blight is a disease that should be pre-empted, once the conditions are right then potatoes should be sprayed to prevent it taking hold. once you have it then it is really too late to combat it. again the likes of Mr Don should be teaching the amateurs about this instead of harping on about all things organic.
to anyone who has an allotment, make sure you remove every last potato no matter how small & ensure your neighbours do too. remove them from site & do not place them on the compost heap as the latest blight strains can overwinter in these "volunteers" infecting next years crop.

[Arnie]

Farmer Jon

I am with you 100% not so sure about denial I feel it's more to do with ignorance as to what blight can do to your potato crop

Kind Regards

Arnie

[peter]

Mail article said farmers "douse" their crops with fungicide to kill off spores, whereas "gardeners tend to avoid using such chemicals".

Oh the sweet voice of the ill-informed, gardeners tend to be unable to obtain such chemicals due to them not being available for sale to the public.

[Tony Hague]

For anyone who wants to read it and is struggling to find it (like I did !) the blight factsheet is here

http://www.potato.org.uk/sites/default/ ... blight.pdf

It contains identification help and some good advice, usual sort of thing:

-Prefer earlier harvesting varieties to reduce chance of getting it
-If you must water, water the ground, not the foliage.
-Learn how to recognise it (It's useful to be able to differentiate early and late blight too)
-if you want to spray, copper fungicide every 10 days during high risk times - it only slows the spread of blight though, does not cure it.
-Cut off and destroy affected foliage
-In a bad attack, leave the potatoes in the ground for 3 weeks after cutting back the top to avoid infecting the tubers with spores.
-make sure to remove all tubers, no matter how small
-rotate your crops

[Primrose]

Just as a matter of interest (because I don't have one) do allotment societies have any rules about how plot owners are required to treat their crops for blight (potatoes & tomatoes). And do the Allotment committees have any power to take unilateral action with tenants who don't conform to the rules, i.e. remove all the offending blighted products without asking the plot owner for permission?

[alan refail]

make sure to remove all tubers, no matter how small

Just out of interest, does anyone know how commercial growers, harvesting mechanically, achieve this?

[Tony Hague]

make sure to remove all tubers, no matter how small

Just out of interest, does anyone know how commercial growers, harvesting mechanically, achieve this?

Yes. They don't.

I have looked in fields which have just been harvested, and the amount of tubers left in the field was very many. Not just little ones that fall through the sieves either, large ones that presumably escaped the lifter.

Having worked in weeding machinery for a good many years, (including volunteer potato detection and spot spraying since 2006) I have seen fields of beans, onions, beet etc where, from a distance, it could be mistaken for a field of potatoes, although they were just the volunteers from the previous year's crop.

Potato blight only survives on a living host; it dies in the soil in a few weeks. The volunteers are central to the problem. This is why I think it is a bit of a cheek blaming amateurs.

[Monika]

A warning to anybody who grows 'Blue Danube' nowadays: they, being dark purple, are really difficult to see in the soil and we always get lots of volunteers the following year in spite of looking for them with a tooth comb!

When, just after WW2, I worked as a potato picker during the autumn school holidays, that was our reward: after the official picking (all by hand then!!), the pickers were allowed in to collect and take home the gleanings. It never occurred to us that if we were not too careful during the first pick, there would be more left over for ourselves! Presumably, we were being closely supervised.

[Shallot Man]

Presumable farmers are able to use stronger chemicals because they have the required certificate for mixing same. Could not our masters in Brussels [that well known mafia family] allow these to be sold to the public premixed.

[Tony Hague]

I don't think the mixing is the end of the story. I'm not sure, but I think some agrochemicals (eg glyphosate) have to be supplied with a measuring cup/device for retail.

With other chemicals, it is not just the dilution that matters, unfortunately. It is the dose, which depends not just on mixing but also on controlled application. Agricultural sprayers apply a lot lighter spray than you might imagine. Some adjust the spray to keep the dose constant with varying speed. if you wave a hand sprayer around there is a tendency to over-apply. Then there is the repetition - how often, and the total dose over the growing season which may also matter; quite likely with blight fungicides that are applied prophylactically. Also, many agrochemicals for commercial use are not general purpose enough for garden use; they have specific label recommendations for crops they may be used in; the safety of the product in those crops is backed up by expensive trials and residue testing. Then there are the chemicals like paraquat which are just a bit too lethal in their undiluted form ...

And don't forget too, that commercial growers are also suffering a squeeze on the chemicals available to them.

[Arnie]

Hi Tony,

Please excuse my ignorance but can you please explain the following

(quite likely with blight fungicides that are applied prophylactically)

Kind Regards

Arnie

[Tony Hague]

As I understand it, the fungicides for blight are not effective once blight has taken hold, but are applied prophylactically - i.e., as a preventative/protective treatment at regular intervals during Smith periods - long warm damp times - when blight is most likely.

Because it is applied repeatedly and has a residual effect, the accumulated residues may matter, not just the amount applied at one dose.