Turf housing goes back to the Neolithic era and was spread throughout the globe, including of course Norway where the Icelanders came from. I've always wondered how they dealt with pests? Does the sod harden somehow?
I've never seen any pest problem in houses or structures built with or using turf in other ways. I have seen an old man picking lingonberries from a turf roof though. Not what I would call a pest..