We have found beer—the traditional lure for slugs—to be very effective, especially when mixed with a little additional yeast. A plastic drinking cup is set into a hole dug in a spot where slugs appear active; the rim of the cup should be level with the surrounding soil. The liquid (in this case we used stout rather than beer) should be added before sunset; the drowned slugs can easily be emptied out in the morning. We have caught as many as six or seven large adults in a single trap.