Rainy winter weather leads to snails, slugs in spring

Last week I said, “First comes the rain, then comes weeds, then comes gophers, rabbits and insects.” But also in that cycle are snails and slugs.

With the moisture this winter, the snail populations are going to be large this spring. The most common snail in the Antelope Valley is the brown garden snail.

Slugs and snails require a damp environment and fairly humid air to survive; they avoid the sun and come out primarily at night or on cloudy days. During the day, slugs pull themselves into the ground through crevices or available holes made by other animals such as earthworms, or they hide under boards and rocks or in other damp, shady places. They usually return to the same place each night, using the same route each time, unless their usual resting place dries out.

If the air becomes too dry, a snail can pull its entire body into its shell and seal the opening with a sheet of mucus, which then hardens, forming a secure closure. It can remain dormant in this condition for as long as four years. You may think you found a dead snail, but unless the shell is hollow, it is just hibernating.

The brown garden snail may take from four months to two years to mature, depending on the abundance of moisture and food. Individual snails may lay up to 100 eggs. Young snails remain in a nest for several days, and then stay close to the area in which they hatched for several months. This can be an important fact when planning a management program, since a large number of young snails in one area is a clue to where the snails are laying eggs.

The best method to control snails is handpicking. It can be very effective if done thoroughly on a regular basis. At first it should be done daily; after the population has noticeably declined, a weekly handpicking may be sufficient.

Overturned flowerpots make excellent traps for daytime collection. Use unglazed pots and be careful to place them on the shady sides of the plants. You can destroy the trapped snails by shaking them from the flowerpot onto a board and stepping on them, or you can crush them against the sides of the pot with a stick and replace the pot without removing the bodies. Crushed snails and slugs make the pots particularly attractive to other snails and increase your catch.

Beer-baited traps have been recommended to trap slugs for many years. The yeast in the beer is what the snails really like. So it is better to use a simple mixture of water and commercial yeast. The problem with these baits is that they must be monitored and renewed on a regular basis.

You can make an ingenious yeast-baited pit trap from a half-gallon size coffee can. The entrance is a rectangular opening cut a third of the way up the side of the can. The can is stuck into the ground to the level of the opening and the plastic cap is left on the can, which cuts down on evaporation of the yeast and prevents larger animals from getting into the bait.

Several types of barriers will keep snails and slugs out of vegetable gardens. Diatomaceous earth works well. However, diatomaceous earth loses effectiveness after becoming wet and is therefore difficult to maintain. Over time it will also be bad for your garden soil.

Some people recommend you can do the same with fireplace ash, but it is very bad for our soil and I would not ever recommend using it.

The easiest barriers to maintain are those made with copper flashing and screens. Copper barriers are effective after rain and sprinkler irrigation. Copper bands are also used for trunk banding of citrus trees, and can last for several years.

A well-tested barrier for keeping snails out of vegetables is a vertical copper screen surrounding a snail free garden area, or copper bands that can be placed directly on the sides of raised garden beds. The screen should be erected 6 inches high and buried several inches below the soil to prevent slugs from crawling beneath the soil.

Chemical solutions include applying bait around the trees and shrubs you wish to protect. Also, apply the bait in areas where snails or slugs might be hiding, such as in dense ground covers, weedy areas, compost piles or pot storage areas. Before spreading the bait, be sure to read the label and follow the instructions.