Soil samples were collected from a field in Wyoming County near Portageville, NY, on 29 October 1992 and 23 November 1993. The field was planted with winter wheat (Triticum aestivum L.) from September 1991 to August 1992, and with potato (Solanum tuberosum L.) cv. Superior from May 1993 to September 1993. Thirty-nine and 45 samples were collected along three transects in 1992 and 1993, respectively. Two species of Pratylenchus were identified, P. neglectus (Rensch) Filipjev & Sch. Stek. (identification confirmed by A. M. Golden) and P. penetrans (Cobb) Filipjev & Sch. Stek. Their combined population densities were 134 ± 18 (mean ± SE per 100 cm3 soil) in 1992 and 195 ± 12 in 1993. P. neglectus was found in all samples, whereas P. penetrans was found in 33 and 78% of the samples in 1992 and 1993, respectively. Where both species occurred together, the density of P. neglectus was 7 to 8 times that of P. penetrans. In both years, spores of a nematode-pathogenic bacterium (probably a Pasteuria sp.) were found attached to the cuticle of P. penetrans (68% with spores in 1993) but were rarely attached to P. neglectus (less than 1% with spores). Although both Pratylenchus spp. are widespread in North America, this is the first report of P. neglectus in New York. Its dominance in the field was unexpected because P. penetrans and P. crenatus Loof are typically the dominant Pratylenchus spp. in potato production regions of northeastern North America (1). The presence of the bacterium, which appeared to be host-specific for P. penetrans, may help explain the dominance of P. neglectus.
Reference: (1) R. N. Huettel et al. Am. Potato J. 68:345, 1991.
