Box caterpillar - do I need to replace all the compost before replanting?

[Koulibiak]

I have two box trees in large pots that have fallen prey to caterpillars. I’ve decided to get rid of the trees as the damage was extensive, and to replant the pots with something else. Can I reuse the compost that was in the pots (mixed with new), or is it not safe to use because of the caterpillars? I don’t have any other buxus in my garden. TIA 🙏

There's a good chance the soil is depleted or has slumped (compacted). Put it in the garden somewhere else, use new soil, slow release fertiliser, and start again to give new plants a good start, particularly in this weather.

It is best to replace the compost with fresh stuff when replanting a container, especially if the previous occupant died. The spent compost can go on your compost heap if you have one, or just sprinkled over the flower beds.

Thank you both 🙏