Symptoms and Effects

Slugs are slimy creatures which can become serious pests in flower beds, home gardens, and greenhouses. They are basically snails without shells, they are not insects. Damage from slug feeding appears as large irregular holes chewed into leaves, fruits and vegetables. Fruits and vegetables in direct contact with the ground are attacked more frequently than those off the ground. Because slugs feed mainly at night, they are often difficult to find during the day when examining damaged plants. Look for shiny "slime trails", a sticky secretion left from feeding slugs.

Life Cycle

Wisconsin is home to many slug species, the most damaging are the gray and spotted garden slugs. In Wisconsin, slug adults and eggs overwinter, and then become active during the warm days of early spring. Slugs usually hide from the sun during the day, and only come out to feed at night and on cloudy days. Adult slugs are ½ to 3 inches in length. They lay their eggs in damp shaded soil, which hatch within three to four weeks. Slugs grow slowly, and may live over a year.

Shaded flower beds and heavily-mulched gardens are ideal habitats for slugs, as they need high humidity and cool temperatures to survive. Slugs cannot survive in direct sunlight for long. Without hiding places during the day, they will quickly die.

Controls

Controls consist of traps, barriers and baits (poisons). For best results use a combination of methods, including good "clean gardening" practices. Remove boards, rocks, and unused pots in your garden to reduce the number of available hiding places.

Traps:

• Sink tuna cans or low dishes into the ground so that they are level with the soil surface. Fill with a mixture of half beer and half water, or 3 teaspoons of yeast per cup of warm water. Slugs are attracted by the smell, then fall in and drown.
• Lay a piece of lettuce or a board out in your garden. Check each morning for slugs and destroy them.

Barriers:

• Diatomaceous earth. This powder is dug from the sea, and works like microscopic glass shards. Slugs that come in contact with it literally dry up. It is non-toxic to warm-blooded animals and earthworms. Spread a thin layer of the dust around affected plants. Slugs must crawl through the powder in order for it to work.
• Agricultural lime. Use like diatomaceous earth. Will ‘dry out’ the slugs.
• Crushed egg shells. Slugs do not like to come in contact with it.

Baits or Poisons:

• Most frequently used baits contain Metaldehyde. Apply according to label directions to soil surface around plants. Do not contaminate edible parts or foliage of vegetable plants. Read all label directions before use.

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