| Helix aspersa, the Brown Garden Snail, is a pulmonate gastropod that is one of the most common terrestrial mollusks. It is native to the Mediterranean and was introduced to Santa Rosa, California in the 1850's as a food source, escargot. It has been disseminated to many parts of the world through the movement of plants, by hobbyists who collect snails, and the movement of infested livestock. It is an invasive pest causing damage to gardens, vegetable crops, ornamentals, cereals, fruit trees, and nurseries. Snails feeding on cultivated plants can cause enormous damage to the plant and crops especially to young seedlings and foliage. The research addresses the identification of specific nematodes and bacterial associates of the snails and the specific locations these organisms occur. I collected 350 snails from six locations: San Francisco, Sacramento, Davis, Woodland, San Jose, and Tulare. From each of these locations snails were taken from residential landscape, vegetable and ornamental gardens, fruit trees, nurseries, and marsh land. Snails were dissected, and nematodes and bacteria were recovered from surface rinsate, the foot muscle, shell, digestive gland, stomach, heart, mantle, and feces. Each snail tissue was plated on differential selective media and 500 individual nematodes emerged between 1 to 3 days from being plated. Each nematode and bacterial isolate was subject to PCR amplification using a variety of primers ranging from the 16S, 28S, 18S, and rpo(3. Nematodes were recovered from ca. 92% of snails and this included Caenorhabditis elegans (60% of snails), Rhabditis terricola (32%), Aphelenchoides fragariae (30%), Xiphinema index (16%), Heterodera spp. (15%), and Aphelenchus avenae (23%). There were 25 distinct bacterial colonies isolated from organ tissues, including Serratia proteamaculans, Klebsiella terrigena, and Stenotrophomonas maltophilia. In addition, there were 5 bacteria isolated from snail slime, including Psuedomonas putida and Sphingobacterium kitahinoshimense. These associations establish the brown garden snail's role as an important phoretic host for plant pathogens, and lead us to consider the possible use of snails as sentinels for the detection of pathogens in the environment. |
