Tomatoes and tomato blight

The current hot weather and last night’s storm have left us expecting to see Phytophthora infestans when we get up to the allotment. It’s the fungus which causes both tomato and potato blight and in both cases the warning signs are the same, brown marks on the leaves which spread quickly and then the tomato fruit will begin to brown and rot away. Underground, if it attacks the potatoes, they too will begin to rot and the blight can spread from one plant to another with astonishing speed.

The fungus is carried by wind and rain and takes a real hold during Mill’s periods which are times of warmth and dampness. It takes around three or sometimes four days of warm and wettish weather to allow the fungus to proliferate, so the first rule to obey during warm times is to water when necessary only and not to spray water on the leaves of tomato or potato plants – water the roots only.

There’s no organic treatment for this kind of blight, so we’ve been having a low level debate about whether to try to prevent/control it or not. We lost all our tomatoes on 235 last year to tomato blight.

To try and treat it, you have to destroy infected plants in their entirety – ripping them out and removing them from the site, preferably burning them to destroy the fungal spores which will otherwise lurk in the soil for years. You can also try to preserve your tomatoes by spraying them with a copper treatment (which is not organic) BEFORE the blight appears. This means that 24 hours into what might become a Mills Period you have to spray … and that’s what we’re debating, because you can always hope that dry weather will slow the progress of the fungus and that by planting with good spacings and removing and destroying any parts of the plant that have blight, you can save your crop – but only if the weather cooperates!

We haven’t reached a decision yet – remain organic and possibly lose our tomatoes or spray with copper and lose my organic principles? Watch this space!

Labels: allotment-potato-blight, allotment-potatoes, allotment-tomato-blight, allotment-tomatoes

Tomato Blight

I spoke too soon when I told anonymous that we didn't have tomato blight. When we saw Duncan yesterday, he said he thought the tomatoes had got blight – sure enough when we got to the plot today, every tomato plant was dark, with blotches on the leaves and the stems, and the fruit had light brown bruise-type marks too. When I got into the tomato bed itself, I saw that many of the fruit had fallen and were greenish-brown. Now I knew they were probably planted too close together and I knew that we hadn't been taking out side-shoots as often as we should have done because we've been busy - so guilt hit me like a large shovel landing in my midriff.

So most of today was spent cutting through the stems of tomato plants and folding deep brown wilted leaves into bin bags. Then I had to gather up all the fallen fruit and bag them too, and finally dig up the stumps. I felt like a failure, a tomato murderer, an allotment monster.

Then I saw Sue – with a punnet of the most glorious tomatoes of all shapes and sizes and colours and she told me that her allotment had got tomato blight too. And that was terrible news and I was very sorry for her, but there was a tiny ray of happiness deep in my heart, because if as good a tomato gardener as Sue could get blight, then perhaps it wasn’t entirely my fault and I wasn’t a tomato murderer or allotment monster after all!

Labels: allotment-tomato-blight, allotment-tomatoes