On Crops: Beans, lettuce, cabbage, Chinese cabbage, tomatoes, and many other garden plants. Unlike most insects, slugs and snails are able to digest tissues from a wide range of plants.
Several species inhabit gardens worldwide, and are especially troublesome in cool, moist climates.
Slugs move about on moist leaves, mulch and soil, and densely planted gardens are a favorite habitat. Slugs can be as small as a pea or as big as your thumb, and all leave a trail of slime behind as they move. Slugs lay their eggs in soil and moist compost, and their numbers can increase rapidly under ideal conditions.
Slugs (and snails) chew holes with smooth edges in leaves and fruits, and small seedlings can be consumed entirely. Slug and snail feeding is most intense at night or during periods of rainy weather.
Wear a rubber glove to hand pick slugs, and drown them in a pail of soapy water. Also monitor slug activity by digging narrow holes 4 inches (10 cm) wide and 6 inches (15 cm) deep, covered with a small board. If you see numerous slugs in the holes after three days, step up other control measures. In areas where slugs are persistent problems, reduce available habitat by delaying mulching for as long as rainy weather prevails in early summer. Natural predators including frogs, toads, snakes, turtles, ground beetles, firefly larvae, songbirds, chickens and ducks eat slugs and their eggs. Slugs get zapped with a mild electric shock when they cross a copper barrier, causing them to turn back. In planters or raised beds, perimeter bands of copper tape can help deter slimy visitors.
Slugs are easily lured into pit traps made by placing an inch of beer in a small open container, and sinking it up to its rim in soil or mulch. Small slugs that are actively feeding on plants can be controlled with caffeine sprays made from cold coffee or dissolved caffeine tablets, but the spray must drench the feeding slugs to be effective. Where slugs are out of control despite the use of preventive measures, iron phosphate slug baits are considered acceptable under organic standards.
First thing in the morning, you can usually see a glistening trail of slime on stems or leaves that have been visited by slugs or snails.