Blight

[starwatcher]

I am thinking of trying maincrop spuds for the first time this year but am worried about blight, how big a problem is it and have i read somwhere that if you get it, it stays in the soil ! Advice anyone

[roitelet]

Rotate the crop - don't grow it in the same place as it was grown last year. Blight is dependant on weather conditions and 2007 was a bad year. If you are in a bad blight affected area I wouldn't advise growing main crop spuds. Earlies and second earlies are better. Get them in the ground as early as possible and then they have a chance to grow as much as possible before the blight sets in. Out here they are planted on the 19th of March (St Joseph) and that way much of the problem is avoided. Last year I didn't plant until 3rd April and lost the lot to blight.

You can spray wth Bordeaux mixture which will help.

Hope this helps a bit.

[Nicos]

We grow Charlotte ( salad spuds) but if you leave them in longer they do grow bigger.In that way, if blight does set in early we can get them dug up and safely stored away.
There are blight resistant varieties om the market too which a few of the Grapes tried out last year..anyone able to comment on them?????

[bluemoon]

Last year was the first year that our lotties were hit with blight - no-one was sure what to do as even the old boys had never encountered it. I'd hate to be in a position though where I couldn't grow maincrops, so we're planting as usual this year and hoping that 2007 was a hiccup. When we realized what was happening we cut the stems off the potatoes to stop the rot progressing to the roots and we still had a crop, although the potatoes were reduced in size due to losing their foliage too early. If this situation continues though I will look at resistant varieties. And of course we always rotate our crops so it will be 2011 before spuds are grown there again.

[Cutecumber]

Starwatcher - where are you gardening? (whereabouts in the country and is it in a garden or on an allotment)

Blight can be a big problem in the UK, but is much less prevalent in Scotland than in the south.

I grow in a suburban garden, and nearly always in large containers rather than the ground because of a lack of space. I stick to the earlier varieties but I also use a maincrop like Valor or Sante, and so far (touching a lot of wood!) I have never had blight on my potatoes. I've been growing them for about 8 years now.

It is likely - at least, this is my best guess - that I miss the blight because I plant and harvest early - much earlier than you would if you follow standard advice. I suspect that my yields are lower than they might be, but at least I get a crop.

I do, however, get blight on my tomatoes, so it's swings and roundabouts!

My advice, then, would be to plant as early as you can (as long as you have good frost protection) and harvest early, even if you have to sacrifice a little extra weight of crop.

[jeannine]

There's always the option of growing maincrops in tubs or containers if blight is a problem in your area - might be a useful back up plan?

[Paul Wagland]

Blight is an airborne fungus - so crop rotation on its own is not a sufficient defence (although it does help, as the fungus affects the stems and tubers too). As soon as you see any sign of infection (dark spots on the leaves, starting at the edges), pull up and burn the affected plants. Do not compost them - the spores will live until next year.

I believe tomato blight is caused by the exact same fungus (toms and spuds being closely related) so keep your crops separate.

Planting early is a good idea, as is removing any decaying material from around the plants. Don't plant too close together and try to water early in the morning, rather than last thing (otherwise the fungus will have a longer period of damp conditions to get settled in!)

[bluemoon]

Sorry to be thick here but I've never quite understood this about growing potatoes and tomatoes separately, I always thought that the idea was to grow members of the same family together; brassicas, legumes, etc because they suffered from the same diseases and therefore crop rotation helped move the plants away from infected ground the following season. I'm not disputing this about toms and spuds as everyone says the same, but I just wondered what the reason was.

[Cutecumber]

Crop rotation helps to prevent the build up of soil based diseases and pests and allows the soil to recover and regenerate. It is about keeping a healthy, living soil.

Blight is an airborne problem and very, very infectious. It doesn't seem to linger very long in the ground so it is not so much the next season of plants that you need to think about but the location and proximity of susceptible plants (potatoes and tomatoes) in any one season.

Does that make any sense?!?

[starwatcher]

PHEW!! Thanks for that everyone certainly given me plenty to think about, I think I will give it a go with main crop. the plan is to plant these in a new plot which we have recently cleared it will be my OH'S plot which she intends using for fruit in the future thought i would use this method to break up the soil and control the weeds then go for planting up the fruit after this. does that sound a reasonable plan ??

[Polly Fouracre]

Would fleece placed over spuds as they are growing keep blight spores off?

[Nicos]

Would fleece placed over spuds as they are growing keep blight spores off?

Good question!
I would doubt it as it is a water-borne fungus and I would imagine it would pass through the fleece with the water droplets.
Blight thrives in warm, moist conditions so wouldn't the fleece create an ideal environment for the spread of fungal spores which are probably already in the soil??

I wonder if a polytunnel would reduce the risk though as my tomatoes in the greenhouse escaped blight this year.

Bit of a waste though growing spuds in that way when you could be growing tomatoes/cucumbers/aubergines etc instead!

Has anyone grown spuds under cover in that way?....and did they get blight???

[bluemoon]

Crop rotation helps to prevent the build up of soil based diseases and pests and allows the soil to recover and regenerate. It is about keeping a healthy, living soil.

Blight is an airborne problem and very, very infectious. It doesn't seem to linger very long in the ground so it is not so much the next season of plants that you need to think about but the location and proximity of susceptible plants (potatoes and tomatoes) in any one season.

Does that make any sense?!?

Yes, thanks for that.

Would using blight resistant varieties all the time be a good idea, or would the disease eventually adapt? I'm thinking here about the way bacteria mutate to become resistant to antibiotics, meaning that using antibiotics when it's not absolutely necessary is counter-productive in the long run. Or does using these varieties mean that the disease is kept to lower levels as it presumably can't reproduce to infect future crops?

[roitelet]

On the subject of resistant varieties, this year I am growing Bernadette which is supposed to be resistant to 'mildiou' which I think is the Frenh for blight. They are second earlies and are supposed to crop heavily and keep well.

We shall see!!!!!

[Paul Wagland]

I'm giving Sarpo Axona a go for the first time... we'll see!

The T&M 'Blight Busters' collection includes the following:
Cara - Late Maincrop
Lady Balfour - Early Maincrop
Markies - Late Maincrop
Valor - Late Maincrop
Sarpo Axona - Late Maincrop
Sarpo Mira - Late Maincrop