The boxwood caterpillar is devastating all the box hedges in the Périgueux
How to spot them:
Look near the tips and the new growth for leaves that are a darker green, then patches will form that look like the plant is dying and the leaves start to disappear at an alarming rate!
The local gardening shops do have some pesticides but you need to spray thoroughly. An organic remedy is said to be rhubarb and mint, but maybe just the poisonous leaves from the rhubarb might work,