"Jeff Layman" wrote
Lily beetle (and its grubs) will eat many liliaceous plants - not just
lilies. They are a real nuisance - so much so, that I have given up
buying anything they may take a fancy to. The only systemic insecticide
available for use today is of the imidacloprid/thiacloprid type. I have
used imidacloprid in the past, but find it has become less effective
(resistance?) than it was when I started.

Dimethoate would be effective, but is unfortunately still unavailable for
domestic use.

If you can't get a suitable systemic then for some reason Bifenthrin
(Polysect) works well too, one spray kept them off all the plants I used it
on for a season. (I had some left over from use on the allotment and tried
it) Perhaps it was the smell?

--
Regards
Bob Hobden