Caterpillars in box hedge

Question

Box hedge 9 yrs old. Last year looking a bit weary. This year seriously leaves dead. But shoots and stems still alive and green
on inspection caterpillars green and black striped curled up in all the leaves
Do I cut back to 10” high and spray caterpillars
Or dig them up
Plant new.
But will the caterpillars be in the soil or surrounding plants and come back

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Answer 1

It may be the dreaded boxwood tree moth. A Bt type spray seems to be most effective. The moth lays eggs on the plant so it is not in the soil. Here are some other insects that plague boxwoods:

https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/controlling-boxwood-insects.htm

https://www.gardeningknowhow.com/plant-problems/pests/insects/prevent-caterpillars.htm

https://www.gardeningknowhow.com/plant-problems/pests/pesticides/using-bacillus-thuringiensis.htm