Published in the Contra Costa Times on May 27, 2006

Q. I have been overrun with snail and slugs—they are eating the peel off of my lemons, my rose buds, the foliage on my plants—I have pets and small children and do not want to use strong poisons in my yard. What are my options?

A. The very rainy spring this year provided the ideal conditions a snail and slug population explosion. These irritating garden  pests are  the bane of many gardeners; particularly considering that they were introduced to California in the mid 1800’s from France for escargot. The common brown garden snail and slugs are Gastropods, (Mollusk phylum), and are related to clam and oysters. They thrive in moist environments with plenty of  plant material for a good food supply. Most are nocturnal,  although on wet days they may come out during the daytime. The mucus trail  is secreted constantly by glands in the muscular foot they glide on. Snail and slugs are capable of self fertilization, although cross fertilization is common. The eggs resemble small opalescent pearls, and are deposited just beneath the plant debris on the soil surface. 80 eggs at once can be laid 6 times a year, which helps explain the population explosion  you are witnessing.  Snail and slugs share similar biology, with the exception of the snail’s outer shell. Your first line of defense is to look for all of the places where the snails and slugs can hide during warm days. Stones, boards, weedy areas, bricks and under decks are favorite hiding places. The habit of hiding under object can be used to trap these pests. Place boards near plants that are being eaten, elevating them slightly with small rocks or bricks. In the morning, scrape off the snails and slugs that have hidden on the underside into a bucket of soapy water. Inverted melon rinds are excellent traps. Copper barriers can be used on trees, large pots and raised beds, but if the population density is high, the barriers are not effective. Some varieties of plants resist damage from snails and slugs including begonias, California poppy, fuchsias, geraniums, impatiens, lantana, nasturtiums, and purple robe cup flower, and many plants with stiff leaves and highly scented foliage like lavender, rosemary, and sage. Most ornamental woody plants and ornamental grasses are also not seriously affected Handpicking is  very effective method of control, but it must be done daily. Go out at night with a flashlight and pick the snails and slugs off of the plants and drop into that bucket of soapy water. Wear gloves. The soapy water can be put on your compost pile, where the snails and slugs can contribute to the soil’s health. Do not use salt to kill these pests—the salt is not good for the soil. If you need to use baits, avoid those containing metaldehyde. Look for baits that list the active ingredient as Iron Phosphate, which is less toxic to children pets and wildlife. For more information call the Master Gardener office (925) 646-6586 and ask for pest note 7427, or download it from the UC IPM website http://www.ipm.ucdavis.edu/