First Report of Globodera tabacum Infecting Tobacco Plants in Quebec, Canada.

Abstract

The tobacco cyst nematode Globodera tabacum (Lownsbery & Lowns-bery) Behrens is a damaging soilborne pathogen of shade and broadleaf tobacco in the United States (2). Nematode infection of roots can cause dramatic stunting, yield loss, and reduce leaf quality. G. tabacum is considered a complex of three cyst nematodes not distinguishable morphologically including G. tabacum tabacum, G. tabacum virginiae, and G. tabacum solanacearum. During 1998, infested flue-cured tobacco plants were harvested in the Lanaudière Region near Montreal, Quebec. Cysts recovered from roots and soil were identified by morphological and morphometric analysis of mature cysts and unhatched juveniles. Although multiple interceptions on nursery stock entering Quebec from infested nurseries in Hartford County, Connecticut from 1974 to 1986 have been recorded (1), to our knowledge, this is the first record of G. tabacum established in Canadian soil. On the basis of historic nematode infestations in this county, it could be inferred that it was G. tabacum tabacum, but further analysis is necessary for definitive subspecies determination. The infested tobacco plants were stunted in the field when compared with noninfested plants. Recently, the production in that area has been abandoned. Because cysts may survive for years in absence of host and also because potato, also a host of G. tabacum, is being introduced on these tobacco farms, it is believed that the distribution of this nematode could expand in the future in this part of the country.