Hello Britta!
Diatomaceous earth is abrasive to crawling insects, like roly-polies, and can be used as a barrier to protect plants. However, it is important to reapply DE after watering, it becomes less effective when wet. Lightly coat the areas where these pests are found or may hide. Repeat treatment as necessary.
Another product you can try is Monterey Ant Control. It’s proven to be effective against pests such as sow bugs and is a safe, organic solution to problems that arise from them. Simply scatter the bait granules on the soil around or near the plants to be protected. In greenhouses, scatter the bait in the pots of plants being damaged or around pots on greenhouse benches.
Below is a link to our page on sow bugs which includes information from life cycle to identification to control with suggested products such as the ones mentioned above.
https://www.planetnatural.com/pest-problem-solver/lawn-pests/sowbug-pillbug-control/
Happy gardening!