Caterpillars everywhere

Went out yesterday and saw the box hedge was looking sad. Looked hard and found some caterpillars .as suspected they are the dreaded box moth caterpillar. As we have a lot of box in the garden I don’t want it to spread from the front to the back. Have sprayed , have cut the worst out but might have to take out completely and replace. The caterpillars are just hatching so may have caught it in time to eradicate them. We shall see.