Is this Manganese deficiency?

[marchogaeth]

I've got problems with one of my Mini White cuc's, despite muck and feeding with comfrey, seaweed and addressing soil pH I think it's got manganese deficiency but I'd be glad for any comments. It is in my tunnel and I'm harvesting fruit from it.
So this is the one I'm worried about:-



It is in my tunnel and fruiting quite well.
This is a close up of its leaves.



This is one that was planted later in the same bed.



Which looks fine, if small.

This is the Crystal Apple, next door which seems to have grown out of it but only just. It is forming fruits.



Nothing else in the poly is showing these symptoms, including the courgette and butternut squashes in there.

I have given them some Epsom Salts now in case it is Magnesium, really need to know not a virus, please.

[mothhawk]

If the Epsom salts does nothing, then maybe it's iron deficiency and they need some chelated iron (sequestrene or similar, or you can get seaweed solution with added iron). I've got a squash like that and I've been looking it up - going to get some iron tomorrow and try that.

[marchogaeth]

How long does Epsom Salts take to work?

[mothhawk]

Don't know, you should surely see a change within a few days? BTW Epsom salts is magnesium sulphate, not manganese...

[marchogaeth]

Don't know, you should surely see a change within a few days? BTW Epsom salts is magnesium sulphate, not manganese...

M, I have edited the original post to make it clear why I used salts. I have looked at Iron deficiency and I don't think it's that, either. Time for more seaweed, I think.

[mothhawk]

Ah, right.
I use seaweed every other watering and two of my squashes are yellow like yours. They are outside so this past few days have had a huge amount of rainwater. I wonder if it is just overwatering washing out all the nutrients (they are in tubs). The ones in the ground are fine, lovely green and I feed them the same.