My choisya is doing ok after a couple of years in the ground, nice flowers
this spring. However I think something is eating it. Just above the point
on the main stems where leaves branch out something strips the bark down
which causes the stem to die above it. It's noticable because the head
turns yellow and then withers and dies. I cut out the dead part and a few
days or a week later another part starts dieing back.

Does anyone know what causes this or how I can stop it?

thanks,
Paul