Something attacking my Lupins!

Hi all,
Up until last week I had the most devine lupins in my front garden. Now however, they are covered in a tiny white bug and seem to have died. Any ideas on what i can apply to them - don't want whatever it is spreading to other plants and shrubs? Also, should i dig them up or cut back hard?
Thanks for any advice.
Peelabee

sounds like greenfly. It may help to spray them - cut them right back I expect they will flower again this saeson