Buddleia Weevil - Cleopus Japonicus

I have a Buddleia Globosa which I recently noticed was looking a bit poorly. The leaves are brown and lacey and on further examination are covered in small slimy golden coloured larvae and small dark grey weevils which appear to have an elongated nose. The underside of the leaves have large single globular eggs. I have searched the Internet and from images found it appears these are Cleopus Japonicus, the Buddleia Weevil, which were introduced to New Zealand as a natural pest control for Buddleia. Quite how it made it to my garden I don't know but I'm not happy as I like my Buddleia! Don't want to spray as I don't want to put other insects at risk and just wondered if anyone else had encountered this very unpleasant bug? Wondering if I should just cut it back hard & remove all of the foliage & hope I don't kill it In the process? Any help or advice would be much appreciated.