From the ArcaMax Publishing, Gardening Newsletter:
http://www.arcamax.com/news/gardening/s-156722-509814
Question: My astilbe and lupines have been badly damaged by slugs.
Should I replace them in the fall or is there still a chance the
plants might come back next year? How can I control slugs organically?
Answer: Both astilbe and lupine have reasonably hardy constitutions,
so I wouldn't give up on them yet. If you can control further slug
damage, the roots should be able to generate new foliage this year.
There are several ways to miminize slug damage. You can hand pick the
slugs. (If you start early in the season, you may be able to keep the
population in check for the entire season.) You can also use beer
traps, or surround your planting with copper slug barrier -- the slugs
won't cross the barrier because, for some reason, their "slime" reacts
with the copper, giving them an electric shock. There are also
iron-phosphate-based slug baits that safely and effectively control
these pests.