The telltale sign that slugs are around -- in addition to your plants being eaten -- is the silvery trail they leave behind. Slugs do the most damage at night. They particularly like young, tender plants and can eat the entire plant or leave large, ragged holes in foliage. They eat leafy greens, such as lettuce, and might even eat fruits or vegetables that touch the ground, such as strawberries, tomatoes, or squash. Hostas are a favorite ornamental for slugs to dine on.
The best bet in reducing slug numbers is to get rid of places they like to hide. They like damp, dark places under boards, rocks, garden debris, and flowerpots. In fact, any of these items can be used as lures. Check under them each day and get rid of any slugs you find. Repeat daily until the slugs are gone. Adding some decaying fruit underneath a board in a damp area will also draw in slugs so you can remove them. Wearing rubber gloves, throw the slugs in a plastic bag, seal, and dispose.
Yes! Slugs seem to be attracted to yeast. Beer placed in a small, steep-sided dish or a discarded food container with a lid is one of the tried-and-true traps they can't resist. If you want to keep other creatures from drinking the beer, simply cut two or three openings about one inch wide in the side of the container, all at the same height. Add beer or a yeast-and-sugar-water mixture to just below the openings. Put the lid on the container and bury the container up to the holes. The slugs will crawl in and drown.
Slugs can hide under larger wood bark mulch, but they dislike pine needles, making it a good choice where slugs are significant pests. Another method to protect plants is to sprinkle abrasives such as dry ashes or food-grade diatomaceous earth around plants. These abrasives are major irritants to slug skin. Slugs also like to congregate underneath outdoor decorative rugs on patios and decks. Sprinkling diatomaceous earth under the outer perimeter of the rug can help keep them at bay. Repeat periodically, as this abrasive becomes ineffective when wet.
Baits are available on the market, such as the brands Escar-Go! or Sluggo. When using baits, place them near dark, damp areas of the garden where slugs typically hide. Follow the label directions and repeat as necessary. The active ingredients in most baits are toxic to humans, dogs, and cats, so use them safely and store them securely.
With a combination of strategies, the slug population in your garden should decrease or disappear.