[AlaninCarlisle]

Yes. blight was confirmed by a commercial grower. What to do now?

First off, this is a heavily shaded piece of land of about 150sq metres that I can afford to set aside next year after too many years of simply growing spuds on it. I have ample space elsewhere.

The problem is that due to the weather most of the spuds under the dead or dying haulms are too small to be harvested and to pick them out as potential 2013 volunteers would take more time and patience than I have so I plan to just take out the larger ones and leave the rest to rot. Sod's Law being what it is, I anticipate that many will survive without rotting and I'll have a mass of new volunteers next spring. I plan to kill these off with glyphosate and leave the ground alone until 2014 when I'll grow stuff in some form of rotation

Given that space is no issue, does this sound sensible?

[mumofstig]

bear in mind that by leaving a lot of the potatoes underground you will be leaving the 'living material' bridge that blight needs to survive over winter,  leave yourself open to reinfection early next year.

As you plan to dig for the bigger spuds, is it so much extra work to lift as many of the smaller spuds as you can, in order to reduce the risk?

[AlaninCarlisle]

I suspect that whatever I try to do, I'll be leaving scores of grape-sized and smaller spuds behind. It'd be like painting the Forth Bridge to try and root out all of these. The good thing is that there are no other blight-susceptible crops anywhere within 50 metres of this patch and no one else growing anything other than pasture within half a mile of us so provided that I kill off any volunteers as soon as they appear, I should have clean land for 2014 or even late 2013

[Jamboian]

Noticed in your post .I ,I I snot about you, do your utmost to reduce blight or go buy your veg at Tesco

[AlaninCarlisle]

Point taken Jamboian , but this isn't an allotment or even a garden with neighbours growing crops. As was pointed out, the only commercial growing in the neighbourhood is pasture and silage so I'm not sure if there is any risk to others by following the plan I outlined. In any event if the haulms are removed and burnt and any "volunteers" killed off in Spring, the risk should be zero

[Aunt Sally]

Yes. blight was confirmed by a commercial grower. What to do now?

Are you certain you have late bright rather than early blight.  It's very easy to confuse.  There are no blight reports in your part of the country at present.

[AlaninCarlisle]

Aunt Sally, I didn't know the difference between early and light blight. I simply asked a small-holder who I occasionally buy stuff off to tell me and he took one look and said "blight", advised me to remove and burn the tops and salvage whatever spuds I can. He did say that the spuds were unlikely to keep and to bury or burn any that go off rather than compost them

[Aunt Sally]

His advice was good if it was late blight but not if it was early blight.

Have your removed the tops yet?  If not please post a picture of the blight on them.

The lesions of early blight do not cross the veins and look a little like concentric rings of brown, hence the other name of target spot.  Late blight just spreads and crosses veins and does not have concentric rings.  Picture if you can me dear

Some of my potatoes have early blight but hopefully they will be fine.

[Kirpi]

What's the general opinion regarding composting blight potato leaves? I am thinking the blight in leaves will not survive winter but to make sure no blighted potatoes get in there or there will be a living bridge to next year.

[Aunt Sally]

No, don't compost it unless you have a "hot heap".  Burning if you can is best.

[Kirpi]

It's a bit late for burining - my potato tops are already steaming in between a sandwich of grass mowings above and below; hot enough to cook eggs in. I think I'll be ok.

[Aunt Sally]

If it's hot, hopefully it will be fine 

[Kirpi]

There also seems to be some concensus that blight will not survive the winter on dead vegetation so the extreme cold could play a part in this, as well as having nothing live to live on until the following year.

The way I understand it is blight cannot survive on dead potatoe leaves but will over-winter on or in infected potatoes if they find their way into the compost bin or left in the soil.

[Aunt Sally]

The fungus can also produce resting spores (oospores) in the plant tissues that can contaminate the soil. Little is known about their survival and their potential as a source of the disease. The investigations into oospores are continuing and more information may be available in a few years.

The jury is still out.

[Kirpi]

Thanks Sally