Verticillium dahliaeandPratylenchusspp: populations in potato soils and plants in Australia

Abstract

The levels of Verticillium dahliae and Pratylenchus spp. were determined in soil and potato plants collected from 77 fields in potato-growing regions of Australia between 1996 and 1997. Verticillium dahliae was detected in soil from 81% of the fields and in plants at 80% of the fields. Densities in soil ranged from 1 to 19 colony forming units per gram of dry soil. Pratylenchus spp. were detected in soil from 87% of the fields and from potato roots at 92% of the fields. Pratylenchus crenatus and P. neglectus were detected in soil from 60 and 27% of fields, respectively, whereas P. coffeae was found in one field in New South Wales and P. penetrans in one field in New South Wales and another in South Australia. Nematode densities over all fields ranged from 1 to 19 nematodes per gram of dry soil. These results show that V. dahliae, P. crenatus and P. neglectus are widespread in potato soils throughout Australia and that V. dahliae densities are likely to be causing significant yield losses within the potato industry. Further research is required to determine the impact of Pratylenchus spp. on potato productivity in Australia.