First brown freckles appear on the stems.
Then the freckles coalesce into nasty leathery brown patches.
The fruit starts to go brown.
What I'm hoping is that the tomatoes at the other end of the bed, currently unaffected, will stay that way, but I think it's likely that I will lose at least a couple more. I'm hoping the ones that are the other side of a zucchini plant to those I've just pulled out will be protected by the intermediary zucchini and not pick up the spores. We'll see. Of course, these plants that might survive are the weediest, least productive tomato plants of this year's crop.
Newly dug Stemster (aka Prospère) potatoes.Last Tuesday I dug the potatoes because their leaves had gone yellow and noticed that some of the tubers closest to the worst affected tomatoes showed signs of blight too, although there didn't seem to be any signs of the brown blotches indicating blight infection on the above ground parts of the plants. I got 14kg of potatoes from 22 plants. Not too bad I thought. They were planted for me by our friend Liselle while she was here in April, and as an experiment I got her to sow some 'wildflower' mix to try to keep the weeds down. It worked very well and was really pretty, but it did make the spuds more difficult to dig.
The potato bed on 1 July, with its gaily coloured 'wildflowers' -- Californian Poppy, Field Poppy, Patersons Curse, Lavatera, Flax, Cornflowers, Arabis, Calendula Marigolds, and several others.
The disease, caused by a fungus like organism, rots the potato just under the skin, causing lesions. Like most of these 'fungus like organisms', in this case Phytophthora infestans, an oomycete, there is no treatment once the plants have the disease. As you have probably guessed, the organism was the cause of the potato famines all over Europe in the 1840s. The only possible treatment by the home gardener is prophylactic applications of copper based biocides such as bordeaux mix, which is so appallingly toxic to man and beast that I really do not wish to use it, especially multiple times throughout the season, just on the off chance there is blight about.
A la cuisine hier: Potato and leek soup, with added courgette, pureed, spiced up with a hint of ras al hanout and enriched with cream cheese. Another two courgettes successfully disguised.