With our wet spring, you may see more slugs and snails than previous springs. Slugs and snails are 'clean-up' creatures, usually feeding on dead and decaying plant matter. But they also enjoy some fresh tender greens, and can invade flower beds, vegetable gardens, and even lawns.
Slug and snail damage looks like something has cut off parts of the leaf and leaf edges. If damage happens before a new leaf unrolls, leaves may have a rows of holes after they expand.
Hosta leaves are a favorite food for slugs and snails. Damage symptoms are ragged leaf edges and holes within the leaf surface.
Both slugs and snails leave a tell-tale trail of slime behind them. This dries to a shiny line, and if an area of ground or leaf surface is crossed by many snails, it looks shiny, especially when the sun is at a low angle in the sky (morning and evening).
Snails and slugs are not the easiest pests to control. Because these pests are nocturnal, you can catch them during the day in their hideouts - under boards, plant litter, thick moist mulch. These hiding places help them conserve their body moisture. Place wet boards, melon rinds, or window screen covered with cut grass or plant trimmings out into the problem area. In late morning or afternoon, gather and dispose of the congregated slugs and snails.
Some gardeners use beer 'traps'. Cups or jars with a little beer in the bottom are buried up to their rims in the soil around the problem area. As the slug or snail slimes its way across the ground, it will fall into the cup or jar and drown. To a slug or snail, beer smells like a rotting fruit, one of their favorite foods. A mixture of sugar water and yeast will also attract them into the trap.
Strips of copper flashing, about 2 inches wide, act as barriers to snails and slugs. Lay them down around areas with especially susceptible plants like hosta. Copper foil is also available and may be applied to the base of affected tree trunks. Because copper oxidizes, flashing and foils must be cleaned every once in a while to stay effective.
Chemical treatments for snails and slugs usually contains metaldehyde. Metaldehyde is toxic to birds, dogs, cats, fish, and other animals. Because of its toxicity, it should be used only in areas where animals can be excluded.
Iron phosphate is another effective active ingredient used in slug and snail controls. Much less toxic than metaldehyde, iron phosphate is safe to apply in areas frequented by pets or children.
More information about Slugs and Snails is available at:
Snails and Slugs, University of California Integrated Pest Management Online, http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7427.html
Slugs and their Management, Ohio State University Extension Fact Sheet HYG-2010-95, http://ohioline.osu.edu/hyg-fact/2000/2010.html
Database of IPM Resources, Slugs: http://www.ippc.orst.edu/cicp/Pests/slug_snail.htm