"Brown garden snail (BGS) is a phytophagous snail which means it feeds on plants, making it a pest of crops and ornamentals. Although intentionally introduced into the United States by way of California in the 1850s as a source of escargot, BGS has been accidentally introduced into the environment and has spread into unintended areas, making it a threat to plant life."
Fresh from the NCDA&CS Plant Industry Division Plant Protection Section:
