Slippery, Slimey SlugsMarch 7th, 2011 by Peg Tillery
Contrary to popular belief, we really can live peaceably with those slimy mollusks in our gardens. Slugs start sneaking and sliding around our gardens each spring when the weather begins to warm.
The “Western Society of Malacologists Field Guide to the Slug” by David George Gordon, published by Sasquatch Books says, “You’ll never be able to eliminate all of the slugs in your garden—as proved by one English zoologist who systematically removed 400 slugs from a quarter-acre garden each night for several years without any observable effect on the population.”
Slugs can live from one to six years. Their eggs are less than one-fourth-inch in diameter and resemble fertilizer beads. Eggs are laid in clutches of 3 to 50; some species lay as many as 500 eggs per year. A slug’s mouth has a tongue like organ called a radula covered with up to 27,000 teeth. Our mucous covered mollusk friends are distantly related to oysters and squid. Slugs moved onto land, developing a lung. The hole on their right side functions like a nose bringing in air.
The slime absorbs water, keeping slugs moist. Alice Bryant Harper in “The Banana Slug: A Close Look at a Giant Forest Slug of Western North American Forest,” by Bay Leaves Press, says, “Water absorbency is why you can’t wash slime off your hands; you have to rub it off, as you would rubber cement. Slime probably has a scent that helps slugs find other slugs. Slime of our native Banana slugs acts as a nitrogen rich fertilizer.”
Locally, find “Rainy Day Slug,” a delightful children’s book by Port Orchard writer Mary Palenick Colborn and illustrated by Sumner resident Lorie Ann Grover. This story is about a very cute and colorful banana slug who wends his way through a home.
Banana slugs are good slugs and we want to cherish them in our woodlands and gardens. If you find any, please try not to kill them. Nudge them back into the woods.
According to wildlife biologist Klaus Richter, our pesky brown, black, grayish non-native slugs “are annuals like our annual plants. They die in the winter. Only their eggs survive. You won’t want to bait for slugs until a problem occurs.” Then when you find munchings eradicate the slugs with an environmentally friendly product or method.
Conscientious gardeners avoid baits with Metaldehyde which can lead to nervous system damage or death in humans and other animals. Slugs feeding on these baits become dehydrated but they can and do rehydrate when it rains so you’re not really killing many of them. Read every bit of the labels for baits containing this chemical, including the hazards section before deciding to purchase these baits. If you have any Metaldehyde products left over in garages or sheds, take them to the Kitsap County Hazard Waste Site for disposal.
A more satisfying and efficient product, out on the market for several years, is iron phosphate, commercially sold as “Worry Free” and “Sluggo.” Other products become available yearly containing iron phosphate. It will not harm plants, humans, other critters or our furry pets. Iron phosphate also works as a fertilizer. It can be a bit pricy but a little bit goes a long way. Use iron phosphate around your prized plants and then let the slugs munch judiciously on other plants. Determine your own tolerance level for slugs.
Please don’t use salt or ammonia to kill slugs. There are too many slugs for this method to be useful. An abundance of salt or ammonia is not good for your plants. Sharon Collman, WSU Extension Educator (now in Snohomish County) is a slug and insect expert. When she explains how slugs will literally turn themselves inside out writhing in pain from salt exposure it changed many gardeners’ minds about using this method ever again.
Many of us do take perverse pleasure in the slice and dice method of slug control though. Go out early in the morning and evening to find slugs. Slice and dice, using a knife, clippers or scissors. Slug family members will come and cannibalize the carcasses. (Yuck!) Several gardeners strategically place flower pots turned upside down around choice plants. Early morning and evening they upend the pots, harvest the slugs and dump the slugs in soapy water to melt them. Alas, the gardeners didn’t explain what to do with the slug gunked soapy water. Perhaps you’ll avoid this method too.
Another way to reduce slug damage is eliminating slug hiding places. Cut back all overgrown grassy and weedy areas near your vegetable or flower gardens. Pick up and compost all rotting garden debris. Plant extra flowers and vegetables so you’ll have some left to enjoy. Believe it or not, there are quite a few plants slugs don’t even nibble: herbs, scented plants, evergreen plants, prickly plants. Ask your gardening friends and nursery staff to recommend plants ignored or avoided by slugs.
Sluggo works on snails too. Our area is getting more and more dry land snails. These pesky critters hitch-hiked in on nursery stock. Use the same methods of control as you would with slugs. When purchasing new plants for your garden look for snails and slugs on the bottom and rim of the containers. Scrape them off and leave them behind. Avoid bringing them home to visit.