[vron]

Hi everyone we have a serious potato problem with my 2nd earlies International Kidney.

They were planted on 18/4/10 (11weeks ago) Every thing was going ok until 2 weeks ago when we noticed that 5 plants had started to go yellow on their top new leaf growth.
 
These were on the end of the first 2 rows right next to each other.  The leaves were a very bright lemon, surrounded by very healthy looking deep green.  All the others plants appear to be ok.
The tubers were planted in 9 inch deep trenches, covered with Humax then a 6-9inch layer of soil, followed by a good sprinkle of growmore and earthed right up. (I'm very lazy and hate earthing up)

We looked at Dr DG Hessayons vegetable problems book and the yellowing looked just like magnesium deficiency, so until we could obtain epsom salts we gave the potatoes a feed of Wilkinsons Super Grow which contains Magnesium.

This had no effect what so ever, in fact within 2 days, 1 plant had collapsed and died, when dug up there was a very poor root system and very few tiny baby tubers, so it was disposed of.

The other 4 affected plants I dug up today, the roots system looks good, but all the baby tubers are deformed and are very few again.

One of the seed tubers was very soft so it was cut open and you can see for yourselves what it looks like in the pics we are posting.  One of the baby tubers was cut open as it to was soft and there was minute white insects inside??
Will post the pics over several posts as there are a lot to see.

Please can anyone help solve this problem.
Vron

[vron]

More pics

[vron]

more pics. These are the 3rd and 4th seed tubers cut in half and the next ones are the deformed baby new potato tubers .

[DD.]

Have you any other variety of spud? If so I take it they are OK.

Have you used any manure on them?

[vron]

And more pics.
Thats the lot folks, hope you can help us.
vron

[vron]

Yes, we had some well rotted 18mth old organic horse manure at the end of last season from Bham University Farm.
Our Maris Bard/Maris Piper and King Edward seem perfectly ok so far, will dig some Maris Bard up on tuesday and see what they are like and let everyone know.

[DD.]

If it really is organic and the other spuds are unaffected, it's not what I was thinking it may be. (Aminopyralid).

[missycat]

I can't really see what the insects look like ...could it be wireworm small white wiry worms...difficult to squash?

Or potato eelworm (very tiny I think) look at http://www.fedaga.org.uk/node/126

sorry don't know how to put in a link

[mobilekat]

I think you are still right DD.

The big issue with Aminopyralid has been is sneaking into places where it shouldnt be!

So much hay, haylage and silage has been contaminated by it its ridiculous!- its already be proven to have been found in bagged organic compost!

And the history of normal growth and then leaves turning yellow matchs the normal occurrence.

I hope I am wrong- and some one has a better idea!

[Yorkie]

But I don't recall aminopyralid affecting tubers like that?

[JayG]

Or potato eelworm (very tiny I think) look at http://www.fedaga.org.uk/node/126

sorry don't know how to put in a link

That's a good link, although even with my not fantastically wonderful varifocal specs on I don't need a magnifying glass to see the cysts on the roots! Vron's root picture is not sharp enought to tell one way or the other, and I have to say that although I have eelworm on my plot the affected spuds were small and few in number, not deformed.

Not much help I know but it is a pest which is fairly easy to rule in or out.

[wise old gardener]

It really does look like Aminopyralid damage. Do you compost your grass clippings, some broadleaf weedkiller lawn applications contain a similar chemical? Sadly this menace will be with us for many years

[Ivor Backache]

The aminopyralid aguement does not explain the isolated five plants that are affected. I have had a similar scenario with two plants in different parts of the allotment. Both main crop (Maris Piper and Desiree) Plants turned yellow and died. I removed the haulms and burnt them but haven't checked the tubers. My problem was potato blackleg which is caused by poor seed. Plenty of info on the net. May be worth a check?

[Iain@JBA]

That is chemical damage.
Possible causes are that something containing a chemical has been put onto the area that the potatoes grow in or maybe someone has sprayed a chemical by accident which has just blown on to them.

Chemical damage causes the strange haulms and malformed tubers.

[vron]

Thank you for all your replies, I will try to give a little more history.

1:  The horse manure was a shared load between ourselves and another plot holder across the way from us, he has not had any of these problems, in fact his crops are looking wonderful.  His potatoes are going great guns.

2: The plotholder ajoining us had a load delivered early this year from the same place and he has no problems either.

3:  We work on a 4 year rotation, all the other spuds are doing fine, the haulms are looking very green and healthy.

4:  The manure was also used on our brassicas/leeks/onions and lettuces with no problems.

5:  We have 2 seperate A-frames of runner beans, the one A-frame is perfect, but the leaves are looking a little pale.  The other A-frame is on the same side as the potatoes, lthese are also looking very pale and one side of the beans have withered and died, so had to resow more r/beans to replace them.

We don't use any weedkiller or sprays on our lottie or at home so that rules out any grass cuttings
After reading Iain@JBA's post I think he is right "chemical poisoning"

Why do I think this, well I am chairperson of our allotments committee and about 3-4 weeks ago there was a malicious attack of vandalism on our plot by another plotholder, whom I must have offended doing my  duty.  No other lotties or crops where touched other than ours.

We have built 2, 12'x10' brassica cages, one night somebody slashed the complete side of one of them and pushed down one of the runner bean A-frames.  The rest of the plot and crops appeared to be ok, this would be about a week before the potatoes showed these symptoms.

My lottie neighbour had thought it was deliberate poisoning but we did not think that there would be anyone that would stoop that low, still you live and learn don't you.

Opinions please.
vron