What's the latest on tomato blight?

[John Yeoman]

How many people have had tomato blight this year? I hear conflicting reports that this has been a bad/good year for outdoor tomatoes in the UK. In several forums, US gardeners have just started to worry about tomato blight. (When I mentioned ‘blight’ in a US forum in 2000, folk thought I referred to botrytis.) Blight as we know it - Phytophthora infestans - seems to be relatively new in America, at least, in some parts.

Here’s a tip that works for me. If your greenhouse is full (the best environment for tomatoes), put a clear plastic awning over the outdoor plants. And water them carefully at the base, keeping the foliage dry. It seems that blight can get a grip only on damp haulm.

A friend in Switzerland lays bare copper wire under her tomato plants. She swears that the plant takes up the copper and becomes blight resistant!

Certainly, I grew a fine tomato crop one year, untouched by blight, when my neighbours’ plants were rotting. Simply under an awning and without copper wire.

Has anyone tried the awning method?

[Nicos]

I'm in northern France and grow all my tomatoes outdoors.
We only got hit by blight about 3 weeks ago on a patch 2m x4m in one corner nearest to the valley and within 7 days all the plants were affected to some extent.
(This was a piece of land which was virgin field until last year when we grew courgettes.)
Within 14 days almost all the fruit were affected. Fortunatley I'd cropped most of the fruit by then. The blight hit about 2 weeks after our first warm rains of the summer and it looks like it'd blown up from the valley.
My nearest neighbours who grow spuds or veg must be at least a mile away!

The plants up against the house sheltered from the wind and rain from that direction ( NE) missed getting blight altogether...so I can see that an awning could be of help, but side protection too

In the UK- north Cheshire - we were hit by blight every single year from mid June onwards...even in the greenhouse where they were watered from the base- using collected rainwater.
It did cross my mind that the spore could well have entered into the open waterbutt from the greenhouse roof.

[Jeanied]

Just started getting blight on my tomatoes in pots on the paving - in the windiest part of the back garden. The toms on my lottie all seemed OK when I checked them yesterday.
I've been picking for a good while so I'm happy!

[John Yeoman]

Yes, it seems that plants grown in the lee of the wind - say, beside a house or on a patio - can escape blight when plants grown in the open go down with it. That's certainly been my experience. But the fact that plants grown under glass can also go down suggests that the factors are complex.

I suspect that even greenhouse plants will be susceptible when high heat and humidity persist for three days or more - the so-called Beaumont point.

[Alison]

In the UK- north Cheshire - we were hit by blight every single year from mid June onwards...even in the greenhouse where they were watered from the base- using collected rainwater.
It did cross my mind that the spore could well have entered into the open waterbutt from the greenhouse roof.

Interesting, I'm not that far from where you used to be and I've never suffered (touch wood ) in the greenhouse or polytunnel and not too badly outside - some varieties seem worse than others and never before late July and it was later than that this year. Long my this continue.