Topic: Potato Blight

[OllieC]

Nice one Bj, very Lord of The Rings!  :P

[Hector]

To Hector, yes, the Blight infection starts in exactly the same way on tomatoes provide it starts on a healthy leaf.  But it obviously can, of course, start in a leaf that is already chlorotic for other reasons

Thank you. one of the things I find hard is that a lot of photos on the net are what people have speculated is blight and many are so different to each other. Advice here much appreciated.

[OllieC]

FWIW, and even though I don't know much, your picture (http://www.allotments4all.co.uk/smf/index.php/topic,53297.0.html) looks a lot more like trace element deficiency - which one doesn't really matter because they often manifest themselves when there's a lack of Nitrogen compounds around... Foliar feed with something & I'd bet on them recovering. I'd use Miracle grow, but that's yet another argument... ::)

[Hector]

FWIW, and even though I don't know much, your picture (http://www.allotments4all.co.uk/smf/index.php/topic,53297.0.html) looks a lot more like trace element deficiency - which one doesn't really matter because they often manifest themselves when there's a lack of Nitrogen compounds around... Foliar feed with something & I'd bet on them recovering. I'd use Miracle grow, but that's yet another argument... ::)

Thanks OllieC....I am so petrified of getting anything contagious.

[OllieC]

Out of interest Hector, what's the drainage like?

[Hector]

I was given 4 pots...two plants look fine (they are in pots with a built in reservoir.
The two pots that have squiffy leaves are regular pots but are looking potbound (shallow pots)

[Kepouros]

I`m afraid I was not aware that Hector`s other thread was being continued here, and I had already answered his query on that thread.  I trust that Ollie will not accuse me of being patronising when I say that I fully agree with his diagnosis (magnesium), but what Hector says about the state of the pots merely confirms my advice that to repot in larger pots with decent compost is probably all that will be necessary..

[Hector]

Thanks to all :) I was interested in both the potato and the toms blight info. Hope I havent confused things.

[delboy]

Foe goodness sake - stop this insane bickering!

Blight - early or late - is probably unlikely at this time, unless in Cornwall or thereabouts.

Has the recent heatwave affected everyone's commonsense?

I've noticed there's a tendency to score points recently, which led to all sorts of spitefulness a couple of years ago, and a welter of people leaving this forum.

[Kepouros]

It is only on reading again through this thread that I realized no-one has actually answered Monika`s original query which began it.  So, for Monika:-

By maintaining a cropping rota your husband is doing all that is strictly necessary to avoid the build up of potato diseases and problems.  The ideal rota period is normally considered to be 4 years, but I use 3 because otherwise I would be short of space.

As to Blight, this does not, of its own survive in the soil for any length of time.  It will normally only survive for up to 3 weeks outside a living host, but as the term `living host` for this purpose means any bit of potato tissue that contains any form of nutrition including half rotted, half withered potatoes themselves it can quite clearly exist for quite a considerable time.

However, as the blight spores are only airborne, and can only be released from some source which is also above ground infection  via the soil is in any case highly unlikely.  Most blight originates from previous year`s potato detritus which has been dumped and not properly disposed of.  Such sources  include dumps of diseased potatoes left by potato farmers, diseased or slug eaten tubers discarded by gardeners, diseased topgrowth inadequately composted, etc, and I suspect that every allotment complex sustains within it its own next year`s source of blight.

With regard to soil precautions, the only one I consider necessary after blight is that after I have finally cleared away the diseased topgrowth I use a flame gun on the bed to sterilise any minute fragments of diseased  detritus that have been left behind and to kill all blight spores lying on the surface.  This means that when I lift the crop 14 days later there is no possibility of healthy tubers being contaminated by live blight spores on the soil surface, and I would reccomend this practice to anyone with a flame gun or flame wand

[OllieC]

I`m afraid I was not aware that Hector`s other thread was being continued here, and I had already answered his query on that thread.  I trust that Ollie will not accuse me of being patronising when I say that I fully agree with his diagnosis (magnesium), but what Hector says about the state of the pots merely confirms my advice that to repot in larger pots with decent compost is probably all that will be necessary..

By that time of the night I'm afraid I could barely see the screen... I take the maximum does I'm allowed of painkillers about an hour before bed & become a bit less coherent! Could be the reason I'm a bit tetchy too!   :-X