I picked a load off my plant yesterday and have squashed them all (they make a bit of a mess), but I am sure I'll find some more to send off to the John Innes centre - they can gladly have them!! Last year I found some on my sage plants too so must remember to check those as well.

I haven't used any pesticides so far because we do use the plant for cooking a lot, and I actually quite enjoy picking them all off by hand....

And yes, I agree with you, why isn't there some new beetle that eats Japanese Knotweed???