blight in the soil

[Geoff F]

Smartie has got it absolutely correct. It doesn't matter what you do on your plot, blight spores are blowing in the wind and they love damp humid weather.

Yes, only grow earlies, or maybe chance a second early crop but, at all cost, avoid King Edward unless you are prepared to continuously spray. I know they are the best ever potato for taste but they are the worst for blight.

There was an article about this in the latest edition of Gardening Which. Resistant forms of potato have been produced in Eastern Europe, but they taste rather bland at best. If I remember correctly, Cara has some resistance and there is a variety beginning with a letter V which is also worth considering (I might remember the name later).

Tomatoes are always at risk. The best you can do is remove infected leaves to slow down the inevitable and grow one of the smaller early maturing varities.

But next summer is going to be so hot and dry that blight won't get a chance to grow.

[svenrufus]

Originally Posted by Geoff F

But next summer is going to be so hot and dry that blight won't get a chance to grow.

Ever the optimist!

I have given up on the idea of spuds, still pretty cheap to buy and a lot of effort to grow when there is such a risk. I am content to have a large patch of Jerusalem artichoke instead, much under-rated in my opinon. If any spuds come up this year from last year's patch, I'll hoik them out as new potatoes.

Would still love to get tomatoes though, love them fresh, and always better than shops. My neighbour at the allotment grem some in a greenhouse, and they lasted better than my supposedly blight resistant ones in the ground - I guess quarantine might be the way forward... But no, while I've got a few blight resistant seeds left over, and assuming (as it sounds) that I can't realistically wait out spores dying off in the soil, I'll stick with the ground, plant early, get the plants as big as poss before planting out, nurture and tend and love daily and keep my fingers crossed. If I don't get any this year from blight resistant varieties, then I may well call it a day on that (and just nick my mums who seems to have no problems)

Thanks for all the comments and experiences. Hope you have a good growing year...
Cheers
Sven

[Cotham Marble]

Originally Posted by smartie

I think that blight is so endemic that it's difficult to know in each case whether it arises from spores in the soil or wind-blown spores.

While spores can be picked up from soils by the wind and become air borne, the highest volume of air borne spores occurs when distributed from infected plants - this is why 'early' varieties appear to be more resistant - they've done their growing/fruiting before the new seasons spores have begun to be dispersed.

Of course in temperate climates the source for all the new spore growth is overwintering spores in the soil so early cropping tomatoes or potatoes still need a blight free medium in which to grow if they are to avoid infection.

CM

[Badger Watching Man]

I don't want to add to the gloom, but I think there's nothing you can do about blight spores. I've heard it said that they come in on the wind and descend onto the plants, so people have had some success putting a 'roof' over the plants to keep off the spores.

Having said that, I think you have to assume that blight spores are present ALL the time, and that it is the levels of humidity, resistance etc that determines whether the plants are affected.

I lost all my tomatoes last year (and the year before), and the only lessons I have are to space the plants as widely as possible to help the airflow and reduce humidity.

[Geoff F]

For me, artichokes start with an F so I don't grow them anymore.

Early potatoes are always worth a go, especially if you chit the tubers to give them an early start.

I've found the article on blight resistant potatoes. Sarpo brand potatoes are resistant but the most resistant varieties don't taste that good. Sarpo Axona and Sarpo Mira for instance but they have produced another, as yet unavilable, which is rated reasonably tasty. Sarpo Una has some resistance and makes a good early.

The old variety with some resistance, which I couldn't recall the name, is Valor which is highly rated for taste.

However, I've given up on potatoes for a while due to Eelworm problems.

[svenrufus]

Originally Posted by Geoff F

For me, artichokes start with an F so I don't grow them anymore.

lol - I live in a veggie household, it makes no difference to us

Apparently jerusalem artichokes are sometimes planted as wind-breaks. I once heard it said that the artichokes catch the wind, then give it rightt back to you

I had so many warnings against growing them when I first got the allotment, 'Oh, once you plant them, you'll never get rid of them' etc. My first thought was 'Woohoo! Edible weeds!'.

Anyway, I digress - thanks again for all the comments. I am resigned to being blighted if I try again, but will probably do so anyway, and whatever happens will happen.

[Brocakat]

svenrufus , the following is a direct quote from My Trusty Copy of Dr. Stefan
Buczacki & Keith Harris' ...... Collins Guide to the Pests Diseases and Disorders of Garden Plants. ( ! 1986 edition ! ) [ I believe there's an update ! ]

BIOLOGY

The fungus persists over winter in diseased potato tubers from the previous crop, either in the ground or more usually on dumps or in undetected seed tubers. When such tubers grow,either as seed in the ground or in large diseased heaps, they sometimes produce infected shoots. Spores may then be blown from them to infect a new crop. Tubers become infected by spores falling from the haulm onto the soil and being washed downwards by rain. Spores are produced and dispersed ONLY in damp conditions and Foggy weather in summer is therefore very favourable to the disease. Infection by blight spores is likely to take place when the temperature does NOT fall below 10 degrees C. / 50 degrees F. and the relative humidity does NOT fall below 75% during a 48 hour period. That is a Beaumont period. MAFF broadcast warnings when Beaumont ( or the comparable Smith ) periods have occurred in the main Potato growing regions and these indicate that commerical growers should apply protective sprays.


TREATMENT

There is little choice in terms of cultivar suseptability to blight but "Arran Comet " , "King Edward " & " Ulster Chieftain " are particularly prone. Since rotten & unwanted potatoes often carry blighted tubers they should not be dumped but buried deeply away from land on which a NEW crop is to be grown. Seed tubers should b eexamined carefully and any showing symptoms
destroyed , while earthing-up may well prevent spores produced on the foliage from reaching the tubers. Several chemicals are suitable for protective spraying but their application may not be generally worthwhile on potatoes in gardens. In damp seasons, however, particularly if Blight is known to have been present in the vicinity in the same or the previous year, a spray programme is a wise precaution. Spray potatoes with Zineb or Maneb in the
1st week in July ( earlier in th eS.W. of Britain & other mild areas) and repeat at 14-day intervals depending on the wetness of the season ( which affects both symptom severity and the extent to which the chemical is washed off the foliage ).

Spray or dust outdoor Toms as a routine for all except the very driest seasons with Zineb or Maneb at 10 - day intervals, begining just after the 1st fruit set. Dust is often most effective in the early morning when dew is present - BUT the fruit must be washed well, before eating. " Unquote.


Try to get some of MAFF's latest leaflet / literature.

And I'm sure there must have been more disease - resitant varieties bred since then.