The mouth parts of wood lice are very soft so I would suggest that slugs or something else have moved in first. The woodlice follow on the softer material and end up being the 'fall guy'. With the area being damp would support slugs or snails. Put some slug pellets down to test the theory.

Thank you. As regards slug pellets I am trying to be organic but must admit this year has been very trying and I think the slugs are winning as always!!!

If you prefer not to use slug pellets, put some black plastic sheet down around the plants and then check under this in the morning. Most slugs and snails in the area will shelter under this and can be removed. I agree with Cutsandgraz that woodlice are the 'fall guys' for most of the evils perpetrated by those terrible gastropods!
Personally I believe they have developed the ability to 'teleport' as the ones I carefully remove from the polytunnel every morning and transport around 100 metres away into long grass are back INSIDE the tunnel next day! And yet the doors are shut at night!
This is a mystery which quantum physicists should be investigating!