Leeks and white rot

I picked a couple of leeks yesterday and one of them seems to have white rot - the other two seemed OK but I am assuming that the rest of the crop are now vulnerable to rot. Has anyone else had this problem with leeks.

The area of the garden where they are growing had not been used for growing vegetables for about 15 years and had suffered from onion white rot in the past - so it goes to show how long the spores stay in the ground. I will try the garlic treatment on the area where I am planning to grow the leeks next year because I am assuming that I will have transferred some of the spores when walking on the soil or using garden tools.

I am considering preparing all of the remaining leeks for the freezer (there are a lot of them) - do I need to blanch them or just cut and freeze - thanks in advance for any advice.

The rot will slow down a lot as it gets colder, so I'd be inclined to leave them alone..cooking leeks it's not too bad if you loose an inch or so off the bottom, is it?

I have OWR on my plot and don't get many that are a total write off.