Snails and slugs are among the most damaging pests in landscapes and gardens, including the UC Master Gardeners Children's Garden, part of the Garden of the Sun. Fresno County Master Gardeners are now launching an effort to manage the pest by releasing small, elongated decollate snails, the common garden snails' natural enemy.

A collection of small raised beds decorated with colorful scarecrows, quaint décor and several rabbit topiaries make up Mr. McGregor's Garden, but this one doesn't have mischievous Peter Rabbit nibbling on the fruit and vegetables. The main problem appears to be snails. Last fall, dozens of garden snails were found feeding on the leaves of napa cabbage, cauliflower, kohlrabi and broccoli plants.

The Master Gardeners have been searching for organic solutions to the problem. Picking them off one by one has been the first line of defense. The Farmers Almanac suggests spreading crushed egg shells to deter snails from garden beds, and we tried it. However, the UC Integrated Pest Management program reports that egg shells are an ineffective deterrent, and we have seen little improvement.

Another solution available to Fresno County gardeners are decollate snails. Decollates are small, thin, tapered and easy to distinguish from the familiar larger, rounded brown garden snails. The decollate is native to North Africa and the Mediterranean region. It was accidentally introduced to Southern California in the 1960s, and has since helped manage snails in gardens and agricultural settings throughout Southern California and parts of the San Joaquin Valley. It is legal to purchase and release decollates only in the California counties of Fresno, Imperial, Kern, Los Angeles, Madera, Orange, Riverside, Santa Barbara, San Bernardino, San Diego, Tulare and Ventura. Because of its potential adverse impact on certain endangered and native mollusks, they should not be used in any other places in the state. Even in counties were decollate snails are permitted, they should not be introduced in or near natural areas because of the potential danger to native snails.

Retired IPM consultant Gary Woods of Fresno is something of a decollate snail enthusiast. He isn't sure how decollates found his western Fresno yard, perhaps coming to his home in a potted nursery plant, but he has appreciated their role in battling the garden snails so prevalent in the neighborhood. He has educated his neighbors about decollates and shared snails with any who would like to try the biological control strategy to control snails and slugs.

“Literature says it takes four to eight years for decollate snails to control brown snails, but my experience is they'll clean them out in a year,” Woods said.

The decollates are easy to find throughout Woods' front and back yards, under rocks and plants and nestled in plant litter. In February, Woods donated about 30 decollate snails to the Master Gardener's Children's Garden. The decollates were dispersed among strawberry and vegetable plants. While not a scientific trial, our experiment may lead to fewer snail and slug pests and less leaf damage in the coming years.