Photographer: Bill Frank Source: jaxshells.org Copyright: Bill Frank (used with permission)
The Asian trampsnail Bradybaena similaris is a small air-breathing and terrestrial snail. The width of the light brown shell is 12 to 16 mm and about 5½ whorls. Growth lines are irregular and sometimes there is a single apical chestnut band. It can live among leaf litter and ornamental plant like Hibiscus species, but has been known to feed on all types of citrus crops and other economically important crops.
With Bradybaena similaris having a wide range of plants it is willing to feed on it makes this snail a threat to greenhouses, gardens and crops grown in the Southeastern United States. These states are an ideal habitat for the Asian trampsnail because of the high humidity found year-round. What makes Asian trampsnails a threat is that is feeds on living plants and not decaying leaf litter like other native snails. The Asian trampsnail has been observed to destroy citrus crops, grapes, legumes, cabbage and mustard green crops. With no natural predators the establishment of this snail in the Southeastern United States will continue.
Self-fertilization is possible in this snail, and can achieve full maturity in 100 days on average and live for about 144 days. The number of eggs produced per clutch ranges from 1 to 202.
The Asian trampsnail was accidentally brought to the United States in the early 1900’s in the plant trade. In this way, it has been introduced into countries all over the globe. It is quite possibly the most well-distributed snail species in the world. The first documented sighting in America took place in 1939 in New Orleans, Louisiana. This species spread into the five Gulf States via the coastal seaports. It thrives in warm, humid environment. Unlike native Texan snails whose diet consists almost entirely of dead and decaying vegetation, the Asian Tramp Snail consumes a vast variety of garden plants, making it a horticultural nuisance.
U.S. Habitat: Found in areas with high grasses and high humidity; especially greenhouses, gardens and the undersides of fallen logs or branches.
U.S. Present: AL, FL, GA, HI, LA, MS, PR and TX
In Southeast Asia some populations of the Asian trampsnail are resistant to molluscicide A study in Malaysia observed the Phorid fly, Megaselia scalaris was able to parasitize the snail larvae and inhibit exponential growth of the snail. Megaselia scalaris is a common Phorid fly found worldwide and could potentially be used again Asian trampsnails that are metaldehyde-molluscicide-resistant populations in the United States. For now, most populations in the United States can probably be controlled by setting up commercially prepared snail baits containing metaldehyde .
If you want to avoid pesticides sort you can set up “beer traps”. Basically, pour beer into a shallow pan, the beer attracts snails and slugs and they can crawl into the pan and drown. Also, continual monitoring of any garden plants can help manage the snail population on an individual level.
Idris, A. B., and M. Abdullah. 1997. The phorid fly, Megaselia scalaris (Loew), as a candidate for managing molluscicide-resistant round snail, Bradybaena similaris (Ferussas). Resistant Pest Management 9:28-29.
Mallis, A. 1982. Handbook of pest control. Cleveland: Franzik & Foster Co.
Wu S.-P., Hwang C.-C., Huang H.-M., Chang H.-W., Lin Y.-S. & Lee P.-F. 2007. Land Molluscan Fauna of the Dongsha Island with Twenty New Recorded Species. Taiwania 52(2):145-151.