Probably transition shock - your description of what you did does not include a period of hardening off for the plants, so if they were under shelter or inside originally, then planting them straight out without hardening off means they've responded to the cooler/colder conditions by producing whitened areas and a bit of die off. The only thing is, when I look at the photos, those whitened areas do rather look more like white fungus, but that might just be a trick of the light off the wet leaves. If the whitened areas are within the leaf, and do not have a fungal fuzz over them, its transition shock.
UPDATED EDIT: I came back on to make suggestions as to what you should do if it is transition shock, but you've confirmed it probably is. It'll be night time temperatures that are the issue - they may now have adjusted already, but otherwise, cover them with something (not something that will touch the leaves though) at dusk and remove it first thing in the morning for a week or so, or till overnight temperatures are good, then leave uncovered on a mild night.
I'm still a bit concerned about fungal growth though - that compost looks to be pretty wet too.