Prevalence and species identification of Pratylenchus spp. in Manitoba potato fields and host suitability of ‘Russet Burbank’

Abstract

The objectives of this study were to determine the occurence and identity of Pratylenchus species in Manitoba potato (Solanum tuberosum) fields with a history of Potato Early Dying disease using both morphometric and molecular techniques. In addition, suitability of the most widely used potato cultivar in Manitoba, ‘Russet Burbank’, as a host for Pratylenchus spp. was determined. During the summer of 2004 and 2005, 283 soil samples were collected from 31 potato fields with a history of occurrence of Potato Early Dying encompassing the major potato growing areas in Manitoba. Pratylenchus spp. were detected in 39% of the fields and densities in soil samples ranged from 45 to 631 nematodes kg−1 fresh soil with a median density of 125 nematodes kg−1 fresh soil. Morphometrics of female nematodes and molecular analysis (polymerase chain reaction followed by sequencing and comparison of sequence data to the GenBank BLAST database) showed that the species of Pratylenchus in potato fields was P. neglectus. Further, the near absence of male Pratylenchus in the soil samples is consistent with the parthenogenic nature of P. neglectus. Potato 'Russet Burbank' was a poor host to populations of Pratylenchus sp. present in two fields. We suggest that the presence of suitable host plants, cereals and canola, in rotation with potato in Manitoba and soil texture have favoured P. neglectus rather than P. penetrans, the most widespread Pratylenchus species found in soil regularly cropped to potato in the Eastern United States and Canada. More studies are warranted to determine whether Pratylenchus spp. such as P. neglectus in Manitoba are causing damage to crops in rotation with potato and if they play a role in the Potato Early Dying disease complex.