Tropical soda apple (TSA), Solanum viarum Dunal, is an invasive, noxious, perennial weed that has invaded large areas of the southeastern United States. TSA is found growing in pasture lands and is spread by cattle, wildlife, and in the movement of sod and hay. Pasture land is commonly rotated into vegetable production. In November 2003, numerous TSA plants were collected from a vegetable farm growing cucumbers and tomatoes. This land in Martin County, Florida was previously used for pasture for grazing cattle. Root galling caused by root-knot nematode (Meloidogyne sp.) was observed. Female Meloidogyne sp. were randomly extracted from the roots and placed in extraction buffer (10% wt/vol sucrose, 2% vol/vol Triton X-100, 0.01% wt/vol bromophenol blue). The females were crushed, loaded on a polyacrylamide gel, and separated by electrophoresis using the PhastSystem (Amersham Biosciences, Piscataway, NJ) (1). The activities of malate dehydrogenase and esterase enzymes were detected using standard techniques (2). Isozyme phenotype and perineal patterns consistent with Meloidogyne arenaria (Neal) Chitwood were observed. Root galling consisted of round, bead-like galls that coalesced as the infection level increased. This is consistent with galling of tomato roots by M. arenaria. Thus, TSA is a potential reservoir for M. arenaria in Florida and throughout the southern United States. The large host range of root-knot nematodes implies that multiple crops may be affected if TSA is not managed in prior land uses. To our knowledge, this is the first report of M. arenaria occurring on tropical soda apple, S. viarum.
References: (1) P. R. Esbenshade and A. C. Triantaphyllou. J. Nematol. 22:10, 1990. (2) H. Harris and D. A. Hopkinson. Handbook of Enzyme Electrophoresis in Human Genetics. North-Holland Publishing, New York, 1976.
