Slugs are soft-bodied, leg-less, slimy creatures that are common throughout the state and are often serious pests in ornamental and vegetable gardens. They may measure up to four inches in length and are yellowish-brown to black in color. Some may be mottled or streaked with darker markings. All species leave a telltale, silver-colored, slime trail wherever they travel. These trails can be seen on foundation walls, basement floors, roads, walkways and plant leave
Slugs require a great deal of moisture and prefer dark areas. They are commonly found associated with moist, dark places such as under boards, logs, stones, decaying organic material, mulch, trash, flower pots and in crevices, especially in shaded locations. Slugs feed mostly at night and hide during the day to avoid the drying effects of sunlight. They feed on many kinds of plants, chewing ragged holes in the leaves, especially those that lie close to the ground. They also feed on molds and decaying vegetable materials.
Control Measures: Don't expect one method to do the job; use a combination of methods
Sanitation - Slugs can often be controlled by eliminating their hiding places. Remove rotting boards and other debris left on the ground. This is most important in shaded areas. Tall and densely growing plants should be thinned to allow for more sunlight and air movements. Unfortunately, it may be impossible to avoid plant damage near rock walls or wooded areas. Avoid heavy mulching of susceptible plants.
Trapping - It is reported that pieces of board or other material not less than six inches square are effective traps when placed on the ground in gardens. Each morning the slugs can be collected from under the traps and destroyed.
Hand picking - An hour spent handpicking and destroying slugs can noticeably reduce their numbers.
Barriers - Metal fly screening, about four inches wide or a copper strip placed on edge and partially embedded in the soil for support, will keep slugs out of an area. Bending the screening to the outside appears to increase its effectiveness. Copper strips, two inches wide, wrapped around trees, will keep slugs from climbing trees.
Slugs will avoid crawling over anything dry, dusty or scratchy such as gravel, sand diatamaceous earth or cinders. The excessive secretion of mucus needed to cross such materials soon exhausts them and they die. A border 18 to 24 inches wide of any one of these materials should be helpful in control.
Baits - Research has shown that beer can be used to control slugs with the nonalcoholic beer having a slight edge. Slugs are attracted to the yeast in the beer and crawl into the dish or pan and drown. Sink a shallow dish or pan into the ground so that the top edge is a bit above ground level and fill it with beer. Put out such traps in the early evening when slug activity starts. Replenish the beer as needed.
If using pellet-type baits, apply them in the early evening just before the slugs begin their activity. Some work best when lightly sprinkled with water after application. For best results, follow label directions carefully. Baits should be placed in such a manner so that pets and other animals cannot get to them.