DALY: How to keep snails and slugs from feasting on your garden plants

During the growing season, gardeners are often troubled by snails and slugs. These organisms have slimy soft bodies, live on the ground, feast on plants, and can be quite destructive. Although troublesome, they can be controlled and their damaged minimized.

Snails and slugs belong to the category of organisms known as mollusks that also includes clams and oysters. Snails have a hard, spiral shell on their backs while slugs lack it. The bodies of slugs secrete mucus that is frequently observed as slime trails when they move from one place to another. Their eyes are on top of small stalks. The eggs are laid in masses in the soil or on plants during the fall and then hatch during the spring. Snails and slugs require moisture for survival. During the day, they hide in moist, cool places such as under logs, plants, rocks or mulch. At night, they become active. Snails and slugs prefer to eat soft succulent plant material, such as seedlings and small herbaceous plants. They consume small leaves entirely and chew holes in larger ones. Fruits that are low or touching the ground, such as tomatoes, are also a source of food. Since they feed during the night, their presence can be difficult to detect. If you observe this type of damage and notice the presence of slime trails, odds are good that snails and slugs are the culprits.

Several tactics can be utilized for controlling snails and slugs. Create an environment less hospitable for them by removing any leaf litter, excessive amounts of mulch, and other similar material from around plants. Such materials should not be thicker than three inches deep. Remove any plant material, such as leaves, branches, and fruits that fall onto the ground. When found, snails and slugs can be physically removed by handpicking and then destroyed by drowning them in soapy water.

A couple of traps can be used, the most popular and well known being beer. The fermenting substance is attractive to these organisms. Place the beer in small, shallow containers in the ground so that the top of the container is even with the soil surface. Remove the dead snails and slugs and replace the beer periodically. Another trap can be made by placing small pieces of certain vegetables, such as cabbage, carrots and potatoes, under a board supported by a couple of rocks. The following day, the snails and slugs can be removed.

Another method of control is the use of diatomaceous earth, which consists of the fossilized remains of hard-shell algae known as diatoms. This material is sharp and abrasive, scratching the bodies of snails and slugs and causing them to dehydrate. This method is particularly effective in reducing damage to seedlings. Diatomaceous earth has to be reapplied after rain or watering because it gets washed into the soil and becomes ineffective.

Several pesticide baits are available for control, and should be used after first trying the other methods. Many products consist of pellets that contain the chemical iron phosphate, which will reduce the snail and slug populations. The material is consumed, and the snails and slugs die from iron poisoning. The material is toxic to pets, birds and people, so use caution when applying. Make sure you follow all label directions and safety precautions when using pesticides.

Despite the problems snails and slugs can cause, they can be controlled, and their damaged reduced. Initiate control methods when the first signs of them are noticed.

Fall is right around the corner, and the time is now to start planting the fall vegetable garden. Gwinnett County Extension will offer a class on fall vegetable gardens on Wednesday, August 27, 12:00pm to 1:00pm at the Extension office located at 750 South Perry Dr. #400, Lawrenceville, GA 30046. There is no cost, but pre-registration is required by contacting the Extension office.

Timothy Daly is the Agricultural and Natural Resources Extension Agent with Gwinnett County Extension. He can be contacted at 678-377-4010 or tdaly@uga.edu.