Snails

It is almost time for the monsoon rains (at least I hope the monsoon rains come this year). Every year when the monsoon rains come, I find lots of snails and other slimy worm-like things crawling around in my garden. I don't like them and want to get rid of them. What can I do?

The snails and slugs, slimy, worm-like snails without shells, are real problems in many of our New Mexico gardens. These snails hide in the soil and go dormant when it is dry. When there is sufficient moisture, from the monsoon rains or from irrigation, they emerge and begin eating the leaves and flowers from our plants. Both the snails and slugs leave "slime" trails that glisten in the light following their passage. This is a sign that they are active. You will see these trails on sidewalks and on the plants. You will also notice irregular holes in the leaves from the feeding from these garden pests.

There are several things you can do to reduce the problem. You can reduce the moisture levels in the upper soil in much of your garden by deep, infrequent irrigation. When the upper few inches of soil is dry, the snails are much less active. However, it is impossible to eliminate all of the damage with irrigation management. You will also want to employ some other methods such as hand picking and disposing, trapping, or use of molluscicides (snail killers).

Hand removal and disposal is not extremely effective unless you work at it often, but it offers a considerable degree of personal satisfaction for people seeking revenge on the snails who destroyed their plants. Be certain to kill them rather than just relocating them elsewhere in your landscape or moving them to some other landscape. Heavy irrigation of the area with snails will often flush them out and onto walls and plants where they may more easily be collected.

Trapping is a commonly described method which takes into account the fact that snails are attracted to beer. Beer is used as a bait and killing agent. In trapping snails, small bowls of beer are placed in the landscape, especially where snail populations and snail damage is high. The snails will crawl into the bowl and die. Different things are said about the best type of beer. Some people say that only stale beer works, others prefer fresh beer, and some have found non-alcoholic beer to be most effective. If you wish to use the beer traps, you may want to experiment to see which works best for you.

Turtles are known snail eaters and are kept in enclosed backyards by some New Mexico gardeners. Turtles may do some minor damage to flowers and vegetables but do much greater damage to the snail and slug population, reducing the net damage to the landscape. Many people become very fond of their pet turtles and feed them dog food in addition to the snails that they eat.

There are also predatory snails which eat other snails, slugs, and the eggs of snails and slugs. They will also do minor damage to plants but will do more good than harm. You may need to search gardening magazine advertisements and classified sections to find the predatory snails, but box turtles can often be purchased in pet stores.

Finally, when all other methods fail, you can use snail baits. These are molluscicides, or poisons which kill snails. (Snails are mollusks, not insects, so insecticides are usually ineffective.) Be certain that you read and follow label directions and observe precautions to protect pets and birds from eating these poisons.

I agree with you, I hope the monsoon rains come to New Mexico this year. Now you are prepared to deal with the snails and slugs which appear in the garden with the monsoons.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

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