Is It Blight?

[spectrawax8]

From horrid experience I'd say its very unlikely until youve got a lovely crop of ripe toms and big tatties then the blight strikes and you lose the lot. Thats what happened my first year down here in the south (Norfolk) lost a 15 m. row of Gardeners Delight in a week all black and horrid. Never seen it before, as all my gardening had been in Scotland where blight is rare due to the colder winters. Indeed so rare that I believe all our seed potatoes come from there, I should know as I used to be a potato inspector for the Ministry of Ag and Fish - this is in the 70's you understand!
Anyway the point is the little blighters only seem to appear in late JUly August onwards depending on the weather of course, so get your Bordeaux mixture on a week or so before the weather turns cold and damp in July. I t worked quite well for me last year - slows up the ravages considerably. Still I grow nearly all my toms in green house now as that is the best prophylactic.

[SlugLobber]

Fantastic thread, thanks. I had some spots on my toms and potatoes, but suspected it to be scorch from watering whilst it was still too hot. Happy to say I was right! Well, it's not blight, anyway...!

[allotmentlady]

thanks sarah......now all i have to do is to stop worrying whether we are going to get it ! lol

[SarzWix]

Some thing cause symptoms which look similar to blight, especially on tomato plants and can cause confusion. These include; botrytis (grey mould), wind burn, sun scorch, magnesium deficiency, blossom-end rot and frost damage.

Botrytis is usually caused by poor greenhouse ventilation, coupled with plant overcrowding. If it takes hold in the greenhouse, it can be almost as devastating as blight, so it's worth keeping an eye out for. Good airflow and hygiene can help to keep it away - remove any affected leaves straight away, and take them out of the greenhouse, don't be tempted to just chuck them on the floor!





Magnesium deficiency is quite common in tomatoes, and is relatively easy to fix - Epsom Salts (available from garden centres and sometimes chemists) either watered in, or sprayed on the foliage will perk the plants up pretty quickly. But if not corrected it can make the plants look scarily poorly!


Mild symptoms


Looking a bit more serious!

I haven't found any decent pictures of weather damage yet... I have some tomatoes that have been well scorched (shade netting slipped, oops!) so I'll try and get pics of those, but, if anyone else can contribute for the frost damage/wind burn pics, that'd be fab!

[scarey55]

Brilliant thread Sarz, thankyou.

[SarzWix]

The August edition of Grow Your Own magazine (out in July) is going to have an article on preventing and recognising blight too, so that should be worth hanging onto for future reference

[lyndap]

Thanks for this.Its put my mind at rest that the patches on my potatoe leaves is not blight...phew.

[SarzWix]

Tomato Blight

Tomato Blight is caused by the same spores as Potato Blight, so it's worth signing up to Blightwatch if you have your tomatoes outdoors, even if you aren't growing potatoes.

Here are some links and pictures of blighted tomatoes.

Tomatoes - treating tomato blight | Problem solving | How to | BBC Gardeners' World

[SarzWix]

Blight of potatoes and tomatoes is one of the main concerns over the summer, especially with the very wet summers we've had for the last few years. So we thought it would be useful to have a resource that can be easily referred back to, with pictures and links, so that if your plants have symptoms you can check them against the pictures.
And if you're still unsure, this is the place to post questions and photos for a second opinion.

Feel free to add any info or links that I might have missed too. (If you post images that aren't your own, please credit the original website)

A very useful service is the Potato Council's Blightwatch, which you can sign up to using your postcode (and any neighbouring ones) to get alerts when Blight conditions have been met in your area so that you can be on the watch for symptoms, and/or spray your plants with Bordeaux mixture as a preventative. Blightwatch.co.uk - the essential service for professional potato growers
You can also read lots of information about blight on the Potato Council's website, although it is aimed at commercial growers a lot of it is relevant for any potato grower
What is Potato Blight? | AHDB Potatoes


Here are some images for comparison, the links under the pictures have more information too;

Potato Blight




How to protect against potato blight



Potato blight - Problems: Veg & herbs - gardenersworld.com

Michigan Potato Diseases - Late Blight