Seen on the BBC web today: Farmers warn over potato blight
Potato blight is spreading following the recent wet weather, the National Farmers' Union has warned.
http://news.bbc.co.uk/1/hi/uk/6271584.stm
Got it on my plot >:( :( :'(
Thought it had to be warm too?
Ours too - all potatoes ruined :'(
Tim - it is here! It's just blinking wet too ::)
how do u know the signs of potato blight?
Yes, this is blight weather.
I've got it - I think I've lost my entire tomato crop.
As I've said on several other threads, if you think you might have blight, don't f**t around wondering whether it is or not, SPRAY THE BLOODY STUFF!!!
That's not much good if the Bordeaux mix is going to be washed straight off again.
The Potato council site is good Fight against Blight bit... no good at putting up links but go to
www.potato.org.uk and search under "Fight against Blight" good maps regularly updated...
:'(
I`ve already sprayed twice in the last two weeks with Dithane, but even that hasn`t been sufficient. Fortunately, although I`ve had to lift the remainder of my Foremost sooner than I expected and will have to lift the Sharpes Express very shortly, the 2nd earlies and maincrop are not too badly affected and I should be able to keep them growing for another few weeks until there is some sort of a crop.
Just got the beginnngs on my site. Some of my second earlies had one or two blotches so lifted immediately. Main crop is okay at the moment. Blight just needs it to be above 10 C continuously and water on leaves to germinate and infect the plant - so past two months have been ideal.
I am hoping my Bob Flowerdew inspired poly roof over my outdoor toms will jeep it at bay - the leaves are all still dry.
How do ya spray when it rains everyday :'(
You don't!!
Sorry to repeat, but this is not it - is it?
That looks like normal die-back to me. My Charlottes are like that, but the tubers are fine. Blight is blotchier and affects the stems as well as the leaves. My lates have just the first signs, but the rest seem fine.
On our site, it always spreads more quickly among the tomatoes. I have never (until now?) had potato blight; only once have I escaped it on the tomatoes (although I've always got a huge crop off them first). Tomato blight is something I've learnt to live with, but I've never seen it this early before.
I've just had to dig up our entire tomato crop, didn't visit the allotment for five days and, bang, every plant showing brown blotches on stems and grey shrivelled foliage of dreaded blight. Never had it before. Must be the weather. Sprayed potatoes as a precaution. Onions also with downy mildew and thick necks - so won't store well. Shallots a complete shambles. On the bright side looks like it's going to be a good year for the roots, beans and squashes!
What's the difference between dilthane and bordeaux mixture?
Bordeaux mix is a copper based preventive which just about passes as 'organic' simply because there isn't anything else. All it does is kill spores on the leaf surface before they penetrate the surface and get into the plant. Dithane is a contact dungicide (once again, it tries to get the spores before they enter the plant; I don't know what its advantages are, but it seems to have some dodgy side effects.
The advantage of Dithane is that it is a far more effective fungicide than Bordeaux Mixture (which isn`t organic anyway). 60 odd years of potato growing have convinced me that although Bordeaux Mixture provides some protection against the initial onset of blight infection, it is of very little use once blight is present in the plant, and the 80% foliar damage which denotes the complete loss of the plant is quickly reached. Using Dithane 945 I have found that even when the plant is infected the speed at which the infection spreads can be reduced, and the 80% foliar damage point can be delayed until the plant has formed something of a crop.
As to the "dodgy side effects", virtually all garden chemicals, whether weed killers, pesticides or fungicides, have some poisonous attributes, and whether sprayed onto your goldfish pond, injected into rats and mice or spread on your sandwiches will have some deleterious effects, so you should use them properly and in accordance with the approved instructions.
I note that 945 is used regularly on tomatoes by even by the most 'thinking' growers.
Quote from: Kepouros on July 07, 2007, 01:15:25
As to the "dodgy side effects", virtually all garden chemicals, whether weed killers, pesticides or fungicides, have some poisonous attributes, and whether sprayed onto your goldfish pond, injected into rats and mice or spread on your sandwiches will have some deleterious effects, so you should use them properly and in accordance with the approved instructions.
That's why I avoid chemicals! I know Bordeaux isn't organic; trouble is, it's no good in precisely the weather that leads to problems.
I have blight on my maris piper boo hoo. I have dug up and disposed of any obviously infested planted and sprayed the rest with Bordeaux - fingers crossed!
HDRA gives bordeaux mixture "Qualified Acceptance" whatever that is
well its defiantly here in south wales, walked to my plot which is last down the path and many had already removed all foliage.
I am glad I took a photo of my wonderful potato foliage three weeks ago before going abroad. Green, luxuriant, beautiful beyond description.
Went to see it today: totally vanished! All gone! Invisible! Disappeared!
Dug some lovely potatoes, though. Hundreds to come, if the slugs don't get them first.
i thought the best thing you could do is cut all the hullms(s?) off to the ground as the blight gets to the tubers through the leaves have done the 1sts will do the 2nds tomorrow
marg
Cutting off the haulm at ground level is indeed the final precaution, as the blight fungus does eventually travel down the stems to the tubers. However, I have always regarded this as the final action when all other measures have been exhausted. The blight fungus does not travel down the stems instantaneously, and how long it does take depends to some extent on the grower.
Removal of all infected foliage as soon as the signs of infection appear will reduce or delay the spread of infection through the plant, and repeat spraying will reduce the chances of remaining healthy foliage being affected. These two measures combined can allow the grower ( and the plant) a further two or three weeks for immature tubers to develop before the plant has to be cut down - and that point is generally reached when approximately 80% of the foliage has been affected.
Certainly, first early potatoes will, by now, have had their day, and there is nothing to be lost by cutting them down immediately, but the tubers of many second earlies are still at an immature stage, and most of the maincrops have not yet even started tuber initiation. For these crops an extra two or three weeks can make all the difference between little or no crop and some crop or a crop worth having.
However, a word of warning (which I have made before on other similar threads). When you cut down the haulm DO NOT rush to dig up the potatoes immediately unless you intend to use them quickly. If the haulm has got blight then the soil surface below it will most certainly be covered with live blight spores, and bringing the tubers to the surface will simply allow those spores to get onto the (still soft) skins of the tubers, which will then rot in storage.
Leave the tubers underground for a full two weeks to allow the spores to die and the skins of the tubers to set.