Q.Something Eating Our Salix Tree
Hi. We have 4 Salix trees in the garden, and this summer one of them has been slowly dying. I decided to cut back all the dead branches today, and found that there are various holes in the branches where something has been burrowing in, and appears to be eating the tree from the inside. Can anyone please suggest what it might be (we live in northern France), and is there something we can spray onto the other 3 to prevent this from happening? Thanks in advance.

Certified GKH Gardening Expert
It sounds like the tree has borers. Here is what you can do:
https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-borer-insects.htm