Learn to control these slimy pests

January 6, 2011

Morning cup of coffee in hand, you stroll out to your garden and find your hostas riddled with holes. The few intact areas are covered by silvery, slimy trails.

Slugs are insatiable plant-chewing mollusks that live on land. Anatomically one large foot with a mouth, a slug and a snail are the same animal except the snail carries a visible shell. The mucus they secrete helps them to move, mate, and defend themselves.

Adding a water feature, such as a small pond, creates a welcome environment for the slug's natural predators: ground beetles, snakes, toads, salamanders, and turtles. Ducks love slugs.

Slugs live and lay their eggs in warm, wet, dark places, so remove boards, bricks, and other damp debris on the ground. Go out at night, when they are most active, and drown them in a container of soapy water. If touching them is distasteful, wear rubber gloves or pick them up with chopsticks or tweezers. Slugs love the yeast in beer and, like frat boys at a party, willingly throw themselves into it. Beer traps only attract slugs within a few feet, however, and are labor intensive. Another option is to use baits containing nontoxic ferrous phosphate. Copper strips jolt slugs with an electrical charge.

If all else fails, throw that morning cup of coffee on them. New research from the USDA shows that a 2 percent solution of caffeine kills slugs, while a weaker solution takes away their appetite.

Snails carry coiled shells on their backs, while slugs have no shells. Common species of slugs and snails are 1/8 to 1 inch long. (Banana slugs found in coastal areas stretch from 4 to 6 inches long.) Slugs and snails are gray, tan, green, or black, and some have darker spots or patterns. They leave a characteristic slimy trail of mucus behind. Their eggs are clear, oval, or round and are laid in jellylike masses under stones in the garden.

Where they live
You'll find these slimers throughout North America.

Their life cycle
Adults lay eggs in moist soil, and the eggs hatch in 2 to 4 weeks. Slugs can grow for up to 2 years before reaching maturity.

Plants they attack
Slugs and snails attack any tender plants, although slugs in particular have a taste for vegetables. Snails can be a serious problem on citrus.

Why they're a problem
Both slugs and snails feed primarily on decaying plant material. But they also eat soft, tender plant tissue and make large holes in foliage, stems, and even bulbs. They may completely demolish seedlings and severely damage young shoots and plants. They may also crawl up trees and shrubs to feed. Both are most numerous and damaging in wet years and in regions that receive lots of rain.

Organic damage control

  • Garden organically so that your landscape is a welcome home for many natural enemies of slugs, including birds, garter snakes, toads, and lizards.
  • Maintain permanent walkways of clover, sod, or stone mulches to encourage predatory ground beetles.
  • Repel slugs and snails with copper strips fastened around trunks of trees or shrubs.
  • Encircle tender young seedlings with a protective barrier of crushed eggshells.


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