Stalking

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Comment by Ian C Dengler on July 11, 2013 at 10:44am

GARDEN VARIETY MACHIAVELLIANISM
MASTER GARDENER: Good snails vs. bad snails

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The large one on the left is a brown snail (bad snail) and the small slender one on the right is the decollate snail (good snail).

Q: Snails have really been chewing up my garden plants and they are so difficult to control. A friend told me that there is a good kind of snail that will wipe out the bad snails. Do you think they will work?

A: Brown snails can cause quite a bit of damage in the garden, especially during the cool damp days of spring. Because snails are most active from evening to dawn, it’s a challenge to find them if you want to hand pick them. I go out to my garden first thing every morning; a Master Gardener friend prefers to search for snails after dark, assisted by a flashlight. Both tactics work well but require regular attention.

Decollate snails are smaller than brown snails and have a slender shell that makes them easy to distinguish from the brown snails. The problem is, decollate snails only feed on small brown snails, not full-sized ones, and I have seen them nibble on tender seedlings when they didn’t have anything else to eat. Nevertheless, many gardeners find them to be a useful tactic in controlling brown snails. I’ve had decollates in my garden for many years and I am sure they help to keep brown snail populations down.

If you would like to give them a try, you should first eliminate as many of the brown garden snails as possible before introducing the decollate snails. The fastest way to do this is to apply snail bait to the garden. It will kill the majority of the brown snails. Because snail bait also will kill decollate snails, you need to wait a few weeks, until the bait is no longer effective, before introducing the decollate snails. Use this time to hand-pick the brown snails, too. Finally, introduce the decollate snails to your garden, placing them in the same damp shady areas favored by the brown snails. Once they are established, the decollate snails will multiply and be on a constant hunt for young brown snails. Before long snail damage should be greatly minimized.

Many nurseries offer decollate snails for sale, and they are also available through internet and catalog sources. If you have a gardening friend who has them in his garden, perhaps he will allow you to collect some to introduce into your garden. I’ve always found gardeners to be exceptionally helpful and generous.