Is this blight

[john4576]

Hello again. I have sarpo mira and Picasso potatoes both planted in April. The Picasso leaves and stems seem to have just about died off and brown. Is that blight or just end of there normal growth. The Sarpo mira some have black spots on there leaves but foliage seems still quite fresh.
When is time to dig up. And how to harvest. Do I need to cut off the foliage first and then wait a couple weeks or just dig up when I decide to harvest say mid October.

[weegie]

Probably not - both varieties are maincrop. See the GYO growing guide.

Maincrop potatoes will be ready towards the end of summer and into autumn. The haulms are likely to die back beforehand and this is perfectly normal – you can cut them down to ground level when they do, but leave the potatoes in the ground for at least another week. This allows the tubers to harden their skins in preparation for storage. Lift the potatoes on a dry day and leave the unearthed tubers on the soil surface for a few hours to dry off. Use any damaged or diseased tubers immediately and place the remainder into store in clean hessian sacks. These are widely available from seed potato merchants and will allow the potatoes to breathe while excess moisture evaporates. Keep them out of light and in a cool but frost-free shed or garage.

I don't know about the black spots but Sarpo mira is supposed to be blight-resistant.

[Thelma Sanders]

It's about the right time to harvest Picasso, so I'd assume that's why they're dying back. Dig what you need for eating now, but leave the rest a couple of weeks for the skins to set.
edit to add " Picasso is ready for harvesting in early September - that's up to three weeks earlier than Cara." https://www.marshalls-seeds.co.uk/pi...s-pid2021.html

Sarpo mira can be left in the ground til you need them I was still digging some in February of this year. Where they had been earthed up they were deep enough not to be frosted

[ameno]

Late blight cause irregular black-brown blotches, which make the affected area soft and limp, and spread rapidly across the plant.
This doesn't really sound like blight. Although with Sarpo Mira, bear in mind that it is resistant to blight, not immune. This means that in a blight year it probably will still get blight, but the infection will spread only very slowly, so it won't pose much actual threat to the plant.

[john4576]

I got some photos but struggling to upload says unable to upload when I click the jpeg

[john4576]

okay think figures out the photos. got some image

[lottie dolly]

I would say normal die back,as right time of year,also blight is dark brown/black,on stems as well as leaves,must see if my main crop down the plot are ready,before the heavens open up for autumn.

[Can the Man]

Looks like normal dying back to me.

[john4576]

thanks sounds like my get something afterall. Pigeons rabbits and some insects dessimated cabbages. Cabbages that remain are full of hundreds tiny holes in all leaves

[Penellype]

Photos 1 and 2 look like normal dieback to me, but I'm not so sure about photo 3 - are these a different variety? If you turn a leaf over that has that brown staining round the edge, blight will have a whitish, slightly translucent appearance on the underside of the leaf. Blight also progresses very quickly, so I would expect these plants to look rather worse today.

[john4576]

Photo3 is Picasso closeup
Photo2 is Picasso row
Photo1 is sarpo mira close up

[Penellype]

In that case I would keep a close eye on the Picasso, but I think the Sarpo Mira are ok for now. If it is blight it will have spread considerably since your photos were taken and I would expect most of the foliage to be brown.

[Mark_Riga]

The 3rd picture looks like blight to me. If it has progressed a lot it is probably time to cut off the tops of the picasso with a view to harvesting next week. I usually empty harvested potatoes out after a few weeks to check there are none going bad. If I find any, I'd repeat after a few more weeks.
I think Sapo Mira have a tendency to just keep on growing and grow past their best. Once I left them too long and the tubers were big but a lot were hollow. I grow Carolus now as they are blight resistant, crop well and I think cook far better mashed boiled baked or particularly roast and wedges.
I need to harvest mine now to hopefully reduce slug damage. There was some on my earlies, a bit more on the next I dug a couple of weeks ago so these need to come out now.

[john4576]

Ok have started digging up the potatoes. 40 or so plants done so far and results all poor. All got white pimple lenticular on. Lots of mini bore holes. Yellow orange thin worm things boring into them.
Few foul smelling mush. That's both the Sarpo mira and Picasso
What went wrong
How prevent that next year. I thought sarpo mira was the most resolute tough survivor any conditions.

[Scarlet]

Wireworms maybe?

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