What is chewing teeny holes in my cupboard?

[FoofOfTheWalkingDead]

I pulled out the baskets that hold my tea and hand towels and found a bunch of dark dust, teeny-tiny bugs crawling around and these little holes. The cupboard above holds cat food and a few dreamies had snuck down behind but the rest of the cupboards which hold cereal and bread etc look untouched. DH suggests fly spray. Will that do it?

I think woodworm and AFAIK fly spray won't kill them.

Oof, thanks. I was hoping it wasn't that. Google says to take the furniture out and spray with permethrin. I can't do this as it's a fixed cupboard in a corner.
I'll have to look under the plinth to see if they've got into the floor, won't I? Has anyone successfully dealt with woodworm?

Woodworm only eat damp wood so sort out the damp problem and the woodworm will go. Unfortunately it is likely to be a leak or issue with something which is affecting the wall behind the kitchen cupboards and so you might have to take them out to fix the problem.

I assume it is an outside wall?

If so then the first thing to do is check the gutters are not blocked and are working properly and make sure the ground level is below the dpc and there aren't any nearby leaky drains. If you take a few pics of the external wall then people might be able to help work out what's wrong.