Silver Birch bug problem?

Hello. New here!

I have a roof terrace with 3 Silver Birch trees on it, in planters, which we've had there for about 4 years. The middle one isn't looking as well as the others, with holes in a lot of the leaves.

Today, I found this green insectoid on one of the leaves, which a helpful person on another forum identified as a Leaf Weevil (Phyllobius maculicornis), and looking that up, I see that it can eat away at leaves in this way.

I've only actually seen 1 single bug, so it's not exactly an 'infestation' and I just got lectured on the other forum about how precious and wondrous insects are and how I should just let it eat my tree, but I'm keen not to let the trees suffer more damage.

Would a spraying with Bug Clear be a good idea..?

Thanks,

Matt

 

Have you got a picture of the tree in question and also a close up of the damage.
Might help as you say, one bug doesn't constitute an infestation.