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I tweeted Thompson & Morgan with a picture of my potatos as I thought they may have blight. They tweeted back saying it looked like the start of it and to try something called bordeaux spray. Can anyone tell me if this is worth the cost i.e does it work?
I've dug a few of the spuds up and theres no tubers or anything just roots.
Any help much appreciated.
Bordeaux mixture - a blend of copper sulphate and hydrated lime - is an age-old treatment for blight. Like all such treatments, it's preventive rather than curative. There is an issue these days with the copper component. Even though technically organic, it's unfriendly to insects, etc, and will accumulate in the soil. There are other options but they're chemical. I'd talk to a good garden centre about the options.
i thought bordeaux mixture was only used on fruit trees?
No, it's also used on grapes, potatoes and other things.
Another person has now suggested it could be magnesium deficiency! Not sure what to do now!
Can you post a photo of the problem?
Here are some photos of magnesium deficiency in potatoes. Scroll down to photos 161 and 162 and see if you recognise the symptoms.
Bah! The link system still doesn't work here. Cut and paste this link into your browser:
EDIT. Oooh! The link system is working now. As is the edit system. Happy days!
Heres the picture I sent T&M and Amatuer Gardener, both came back with either blight or Mg deficiency. Looking at the photos you linked to Italophile it looks like Mg deficiency to me?
I think you're right. It doesn't seem to have blight's characteristics. Here's blight:
got it too i think its blight as it has also occurred in my container potatoes but not the ones in my greenhouse.
my potatoe leaves have gone yellow,splodges of brown on them,then quickly all the leaves fell and died.these are in bags,i got some very small potatoes ,not sure if it is blight?with the awful weather im just leaving them in the bags.i give up.
Copper suphate and washing sode should not cost anymore than a fiver
At the begining blight shows as a few single brown spots scattered over your crop. If you turn the leaf over you will find a dusty white mould growing, these are the spores ready to spread . A few spots will turn into a lot over the coming week and will quickly show a disease rather than a cultural problem. Blame the rain and it wont get better as the forecast is poor for the next month so im afraid if you grow spuds and you havent got it yet you soon will have.