Twinned together like that – they look like nothing more than 2 names from a litter of wriggling puppies – somehow Border Collie comes to mind…but it’s tomato troubles that we’re at – not so cute and cuddly – although the teeth might be as sharp -and most definitely unwanted intruders into our garden idyll. The fact the entry on blight is not that extensive, and is listed after quite a few other tomato foes – makes me think that it was not the big baddy then that it is now….and I’m not sure I’d say first signs are a downy white fungus – but maybe I just wasn’t eagle-eyed enough to spot that intial stage…Interesting also that he recommends copper based sprays to control – but once the plant has intial signs – whereas now I think if you’re going to spray with a copper based product ( e.g.Bordeux Mix) then it’s as a preventitive barrier – on the upper sides of the leaves where rain will land and perhaps on the under side of lower leaves to protect from upwards splash. And as for Streak – unless it’s been “rebranded” I’m not so sure it’s a common problem now.
Blight
This disease is caused by the same fungus organism that is responsible for Potato Blight. It mainly affects outdoor crops and is recognizable by a white downy fungus growth on the undersides of leaves. These patches of down later turn to blackish-purple areas edged with white. The disease may also attack the fruit and cause large dark-brown or blackish-brown blotches. Sprays with a copper base, as used for Potato Blight, will usually control this disease if used as soon as the trouble is identified. It is essential, of course, that the undersides of the leaves are throughly wetted by the spray. The disease rarely appears in glasshouses unless they are leaky and draughty. If it does occur the temperature should be raised and dry, well-ventilated conditions maintained.
Streak
This trouble is most likely to occur on plants of poor vitality. Whilst it is carried from plant to plant in the same way as the Mosaic diseases it is, in fact, an indication of an unhealthy plant, probably brought about by an unbalanced soil, deficient in potash.
It is recognisable by a distortion and mottling of the leaves, which later carry dark-brown markings; by brown cankered or dead streaks on the main stem, and by brown sunken pits on the fruit. If these symptoms are recognized, a dressing of sulphate of potash should be applied at the rate of 2 oz. per sq. yd and watering and ventilation so arranged as to encourage rapid healthy growth.
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Here in soggy Manchester blight is always a problem and on our allotment site we get it on indoor-grown tomatoes as well as outdoor, at least in wet summers. Agree with you that I’m not sure about the white mould/fungus – blackish-brown patches on leaves are what I look for. We have been fairly successful at keeping plants going for some time by picking off all affected leaves straight away and burning them. If the fruit is already developing by the time it hits, then you can usually get a reasonable crop, with vigilance! Once patches spread to the plant stems it’s too late, as you will end up with it in the fruit, in my experience.
It’s a problem mainly with later fruiting varieties, so in a wet year we find it harder to get a good crop of plum tomatoes. Any suggestions for nice, blight-resistant or not-too-late plum varieties gratefully accepted!
Nice site /blog by the way
Hello
Thank you for stopping by and getting in touch. Your approach – looking for the dark patches on the leaves and picking them off pronto – is what I do as well – I remember last summer looking out of the window upstairs down onto the plants – and seeing some dark patches on the topmost leaves – I was down the stairs, out into the garden and “culling” those leaves before they knew quite what had hit them!
I am wracking my brain trying to think if I have come across a plum variety that is also stated as blight resistant – all that is coming to mind are the cherries – which I think are Koralik and Matt’s Wild Cherry – and for standard – Ferline and Legend. I have seen one or two others in this year’s catalogues but I still don’t think they are plum. My problem with plum seems to be Blossom End Rot – so getting the watering right is my challenge!
Here’s hoping for a dry, sunny summer – even in Manchester!