Photographer:John T. Griffth Affiliation: San Diego Reader Source:sandiegoreader.com Copyright: public domain
The decollate snail (Rumina decollata) is an inch long terrestrial snail that is uniformly tan to light brown in color. It is common for adults to have the tip of their coiled shell broken off (decollated).
Decollate snails are omnivorous and thus can be harmful or helpful to garden landscapes. As a predator, the decollate snail is useful with the control of the herbivorous brown garden snail. However, the decolallate snail is also herbivorous, and if there are no brown garden snails or other alternatives the decollate snail can cause serious damage to landscape plants.
Decollate snails are active mostly at night and during overcast or rainy weather. During the day they hide in leaflitter on the ground and in the top 1 inch of soil. Eggs of decollate snails are laid in masses under piles of debris or in the soil. The eggs typically hatch within a month after they are laid if conditions are favorable. The shells are hardy which allows the eggs to incubate for longer periods if the environment is not suitable.
Introduction of the decollate snail was intended for use as a biological control of the brown garden snail (Cornu aspersum). The snail was first introduced in the 1800's in Charleston, SC.
Habitat: Decollate snails are commonly found in landscape plants where they feed on other snails and slugs or vegetation.
U.S. Present: Throughout the U.S., but highly concentrated in the southern states from California to Pennsylvania
Texas: Austin, Abilene, Beaumont, Dallas, San Antonio, Guadalupe river, and San Angelo
Decollate snails can easily be removed using a combination of methods involving habitat modification, hand picking, trapping, barriers, and bait. Modifying habitats can help prevent any kind of pest snail through removal of hiding places such as clumps of vegetation or piles of brush.
Batts, J. H. 1957. Anatomy and life cycle of the snail Rumina decollata (Pulmonata: Achatinidae). The Southwestern Naturalist 2(2/3): 74-82.
Fisher TW, Orth RE, Swanson SC. 1980. Snail against snail. California Agriculture Nov.-Dec.: 3 pp.
Pilsbry HA. 1946. Land Mollusca of North America (North of Mexico). Academy of Natural Sciences Philadelphia Monographs No. 3, 2:1-520.