[martcol]

Duh my first leeks this morning and one had like a fluffy dew on the part in the soil. Is that as bad as I think it is!  The white had started to turn an ivory colour.

[martcol]

Another image

[mumofstig]

Were the roots also rotting away, so that the leeks could be pulled out easily? If yes, I'd say it is onion white rot or basal rot.

[Dev]

I would agree with Mum. If it is white rot you won't be able to grow any alliums (leeks, onions, spring onions, garlic) there for a long period of time - supposedly 7/8 years. I have it on part of my plot but not on others, but the spores can allegedly be carried on your boots so be careful where you tread!