Pests in Gardens and Landscapes: Quick Tips
Snails and Slugs
Use a board that is raised off the ground about an inch to trap snails daily.
Slugs and their damage.
Brown garden snail.
Snails and slugs rank among our most despised garden pests. These slimy mollusks emerge from hiding at night and chew holes in leaves and flowers of many succulent garden plants and fruit. Slugs and snails are similar in structure and biology, except slugs lack the snails’ external spiral shell. Management requires a vigilant and integrated approach that includes eliminating moisture and hiding spots, trapping, setting up barriers, and handpicking. Baits can be helpful but by themselves don’t provide adequate control in gardens that contain plenty of shelter, food, and moisture.
How do you know snails and slugs are causing damage?
- You might not observe these pests at first, because they feed at night and hide during the day. Go out at night or in the early morning to view them in action.
- Other pests can cause holes in leaves, flowers, and fruit. Look for the shiny, slimy trails slugs and snails leave behind.
What must be done to reduce snails and slugs?
- Remove daytime hiding places—ivy, weedy areas, debris, and boards.
- Regularly remove snails from shelters you can’t eliminate such as low ledges on fences, undersides of decks, and meter boxes.
- Place traps in your garden and dispose of trapped snails and slugs daily.
- Reduce moist surfaces by switching to drip irrigation or sprinkling in the morning rather than later in the day.
- Consider snail-proof plants such as impatiens, geraniums, begonias, lantana, nasturtiums, and many plants with stiff leaves and highly scented foliage such as sage, rosemary, and lavender.
How can I manage snails and slugs without using pesticides?
- Make sure the garden is mollusk-free before planting. Then erect a copper barrier around it. Use a 4- to 6-inch wide band of copper, buried an inch below the soil and bent over at the top or attached around the edge of a raised bed.
- Place your garden in the sunniest spot possible. Remove garden objects or adjacent plants or ground cover that can serve as shady shelter. Reduce moist surfaces as much as possible.
- Build a trap using a 12- by 15-inch board raised off the ground by 1-inch runners. As mollusks collect under the board, scrape them off and destroy daily.
What about baits?
- Baits won’t be very effective unless you also remove shelter, food, and moisture.
- Metaldehyde baits are especially poisonous to dogs and birds. Metaldehyde also loses its effectiveness rapidly in sunlight and after rain or irrigation.
- Iron phosphate baits are safe for use around dogs, children, and wildlife.
- Irrigate before applying bait and apply in the evening on warm days when mollusks are active.
- Scatter, don’t pile, bait around sprinklers and in moist, protected areas where mollusks travel.
Minimize the use of pesticides that pollute our waterways. Use nonchemical alternatives or less toxic pesticide products whenever possible. Read product labels carefully and follow instructions on proper use, storage, and disposal.