Nematode and bacterial associates of the invasive Brown Garden Snail: Helix aspersa
K. SANCHEZ (1), C. Pagan (1), S. A. Nadler (1), E. P. Caswell-Chen (1)
(1) University of California, Davis, CA, U.S.A.
Phytopathology 100:S113

Helix aspersa (Brown Garden Snail) is an invasive terrestrial mollusk. It is a pest of plants and can damage young seedlings and foliage. We collected 350 snails in California (San Francisco, Sacramento, Davis, Woodland, San Jose, and Tulare) to identify associated nematodes and bacteria, and to determine snail tissues where nematodes and bacteria occur. Snails were dissected, and nematodes and bacteria were recovered from surface rinsate, the foot muscle, shell, digestive gland, stomach, heart, mantle, and feces yielding 500 individual nematodes. Nematodes and bacterial isolates were subject to PCR amplification using primers for ITS, 16S, 28S, 18S, and rpoβ. Nematodes were recovered from ca. 91% of snails and included Caenorhabditis elegans (in 60% of snails), Rhabditis terricola (32%), Aphelenchoides fragariae (44%), Xiphinema index (24%), Heterodera spp. (28%), and Aphelenchus avenae (45%). There were 25 distinct bacterial colonies isolated from organ tissues, with Serratia proteamaculans, Klebsiella terrigena, and Stenotrophomonas maltophilia recovered, and five 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.