Birch beetles

That's the problem, Sheal, thiacloprid is now being spotlighted as a Bee Killer and that is the main ingredient of Provado.

 

Sorry to get here late but I was out all day yesterday.

It does look like a birch leaf and the blue beetle appears to be correct. They do look slightly large for a blue beetle which tends to be less than half an inch, but they may be smallish leaves.

I, also, don't use chemicals in the garden so am not able to advise on treatment. A slight correction to my previous sentence: a few years back I had to use a killer for a really bad infestation of viburnum beetle. I have a number of large viburnums and so do my neighbours. The viburnums were starting to die back from the attack and the neighbours asked me to use the killer. Which I did, after advice from the RHS.