Have you found tiny little caterpillars munching away on your Aruncus Sylvestris leaves? They are the larvae of the sawfly.
You might notice first that the leaves on the Aruncus are skeletal with just the veins remaining and wonder what has happened to them. Take a closer look and you will probably find these tiny larvae, which are so small and so well camouflaged you might even miss them at first glance.
If I notice them at this stage I pick off the larvae and put them on the bird table as a takeaway meal for the birds. If I don’t spot them, hopefully the birds will find them on the plant.
I never spray them though as they do no lasting damage to the plant and it will continue growing and flower quite happily.