[AnneB]

I planted all my potatoes out on 4th April.   A week earlier than usual for me due to holiday. Growth seems to be a bit behind on all varieties this year, I put that down to the cold and windy weather.  Mine are all about 10" high and none has flowered yet.

I am growing Sharpe's Express, British Queen, Vivaldi, Ambo and Setanta, plus a few Casablanca in a barrel at home.

Last week I noticed the Vivaldi yellowing a bit with a few dark spots and I wondered if they had a mineral deficiency, so gave them a foliar feed.   Today it is clear that they have a bad case of early blight as it is a lot worse.    I don't think it is a mineral deficiency as the British Queens in the other half of the same bed are perfectly healthy.    I had a furtle around and there seems to be a good crop developing, plenty of spuds but still a little small.

Has anyone else noticed that Vivaldi is susceptible to early blight?

Should I spray them?  Or just remove the affected leaves (which would be a good 80% of the foliage)?

Any thoughts gratefully received.

[Baldy]

We've had a large number of different varieties on different plots that have somewhat 'blight - like' symptoms but the general consensus here is that some varieties in some more exposed positions have been hit by cold (either frost or wind). I am inclined to agree but have no scientific evidence to support the hypothesis. 

Pip pip,
Balders

[Growster...]

Like Balders, I have no scientific experience, Anne, but a general thought would be that they got clobbered by the cold weather in the Spring, and you have spied some reasonable sort of crop, regardless of the mineral deficiency you refer to, which would presumably apply to the others in the bed.

Our 'Swift' have haulms nearly devastated by slugs, but the crop is mostly pretty good (thank goodness),  so I'd consider that your 'Vivaldi' are victims of bad weather, not the conditions that you're growing them in!

Looking at the Wiki entry on 'Vivaldi', they seem to have a very individual persona, so you may well be pleasantly surprised!

[AnneB]

Thanks both.  I have found the attached link which suggests that Vivaldi are susceptible to Alternaria (or early blight).   I think this is what they have got.

I have never had early blight on potatoes before.   I am not sure if I should spray or get rid of the affected foliage, or just ignore it.   Will it make a lot of difference?   The guidance suggests preventative spraying, but I am sure that this is for commercial growers.

http://www.hzpc.com/uk/pdf2/VIVALDI2.pdf

[Growster...]

The trouble with preventative spraying, is that you find out when it's too late, unfortunately.

If it was my crop, I'd still be down there soaking it with soluble aspirin, and Bordeaux if you can get it, but if the haulms are really bad, then do what they suggest for Late Blight - just cut them off, and lift the crop in a couple of weeks?

Rotten advice really - sorry, but you will at least get some second earlies if you can store them safely!

I hope you'll get a result anyway!

[mumofstig]

just remove all the brown marked foliage, if it gets really bad remove all the tops, and expect a reduced harvest.
Nothing else to do really.

[Salmo]

If they were mine I would ignore it. If the weather becomes less humid, as forecast, it should not spread. It does not usually affect the tubers like late blight.

[grinling]

blight...brown patches, no yellowing, underside white mould ring

Aphids

yellow blotched...frost

browning between veins...yellowing, turn brown, stunted growth.  magnesium deficiency..feed with fertilizer with magnesium/phosphates/nitrogen/potash. 

Check all 4 add feed if not already. Depends on last crop in that area as well as drainage for the nutrients.

[AnneB]

blight...brown patches, no yellowing, underside white mould ring

Aphids

yellow blotched...frost

browning between veins...yellowing, turn brown, stunted growth.  magnesium deficiency..feed with fertilizer with magnesium/phosphates/nitrogen/potash. 

Check all 4 add feed if not already. Depends on last crop in that area as well as drainage for the nutrients.

It is definitely not a mineral deficiency, the soil is good, manured in winter and the British Queens in the same bed are unaffected by the leaf symptoms.    It isn't frost either, nor aphids, it is not late blight, (none in the UK yet according to the map) but it is definitely early blight, which is something different altogether. And which I haven't had on the plot before.
   
I am going to remove the worst of the yellow mottled leaves and spray with diluted aspirin and see what happens.

[grinling]

2 different potatoes will use minerals differently. farmers use different amounts depending on the crop in different parts of the same field.