[Ma Lowe]

I have heard that some on our allotment site have got blight. The wind blows a gale in my direction so if it's true then no doubt mine have it too now. Do I dig up all the potatoes now. Foliage seems fine on mine just going the usual yellow colour.

[mumofstig]

wait until you see it on yours, then follow advice in my earlier post!

If it is blight don't dig them up quickly - cut the tops off and leave the potatoes underground for a fortnight, they've got less chance of getting live blight spores on the tubers when you dig them up then, than if you do it straight away.

RHS advice

•When infection levels reach about 25 percent of leaves affected or marks appear on stems cut off foliage (haulm) severing the stalks near soil level and raking up debris. When the skin on tubers has hardened, after about two weeks, the tubers are dug up and stored.

http://rhs.org.uk/Advice/profile?pid=217

[Ma Lowe]

Ok will keep an eye on them for now.

[wendycas]

Hi
We spent yesterday cutting foliage off our 4 potato beds......4 days ago the pots were lovely and lush, yesterday the majority were yellow with black spots on  Does the foliage we've cut off need to be bagged straight away as we've left a pile on the allotment?? The other thing was, we lifted a few plants to check on the tubers and a lot had holes in-these were maincrops that had gone in in May so they weren't due out til September. We haven't over watered and we haven't had much rain-any reason for the holes?

Also, we had blight last year too-in a different place (we've been really strict re rotations)-is there something we are doing wrong or something we should be doing?? 
Cheers
Wendy

[mumofstig]

There has been a lot of potato damage from slugs this year, after the very wet winter 

Yes, it's best to bag and dispose of or burn the blighted foliage, to stop the blight spreading further.

Blight spores are wind blown, not a lot you can do unless you spray.

[wendycas]

Hi
Thanks for that. You mentioned spraying-when is the best time to spray and how often during the season? Also, are there any organic things to spray with or just the inorganic ones.
Thanks
Wendy

[mumofstig]

The Forum Blight advice is here
http://chat.allotment-garden.org/index.php?topic=56717.msg668473#msg668473

All the sprays available contain copper, and organic farmers use Bordeaux mix, also copper based.

[yorkiegal]

I discovered signs of blight on my spuds yesterday, on the two plants at the end of my row. I removed them completely. No tubers yet, and flowers only just starting to appear so I don't know whether it's worth spraying the rest and crossing my fingers that they survive long enough to produce a crop. They were a supposedly blight resistant variety and were due to be ready around november. 

[New shoot]

The blight resistent varities can show signs of blight but not actually get destroyed by it.  My Sarpo Mira have had signs of it for a while, but they soldiered on and are now getting to the stage where they are ready for lifting.  I haven't sprayed, but mine were only a few weeks off harvest.

If yours are ready in November, are they in a polytunnel - was just thinking they must be under cover for frost protection 

[yorkiegal]

they're not covered as yet but will be before november. my cheap polytunnel collapsed last year so it's been cut up and made into a mini tunnel about a metre high, which i can move around the plot.

tbh i put the spuds in mostly to improve the soil on a part of the plot which hasn't been worked for a few years, so if the blight does get to them i'll just dig everything up and plant some green manure in there.

[Ema]

Received blight warnings for my area yesterday, still got 2 rows of main in. Busy week ahead hopefully I'll get chance to take the foliage off this week