Rev 08/31/2026
Chromadorea Rhabditida Tylenchina Tylenchoidea Pratylenchidae Pratylenchinae
Pratylenchus flakkensis Seinhorst, 1968
Ref. Seinhorst, 1968
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
The type locality of P. flakkesisis described as being near Middelharnis, The Netherlands with other known collections from Ouddorp, Netherlands and Beckenham, England. The type locality was described as a pasture on loam soil (Seinnhorst, 1968).
Gnerally, species of Pratylenchus are difficult to identify because many have overlapping morphometric characteristics and because available molecular databases may include misidentified sequences from nematodes that were originally mic-identified.. Subbotin et al. (2008) developed a phylogenetic framework for Pratylenchus species using partial 18S rRNA and D2-D3 expansion segments of 28S rRNA. Janssen et al. (2017) emphasized the importance of linking molecular data to accurately identified voucher or topotype material and provided DNA sequences for P. flakkensis,
As of 2026, Pratylenchus flakkensis has not been reported from California. Because of the damage potential opf this and other species of the genus, it has been assigned an A-rating in the in California Nematode Pest Rating System (Martin, 2026)..
Migratory endoparasite.
Root-lesion nematodes are migratory endoparasites. Juveniles and adults enter roots, feed within the cortex, move through root tissue, and may leave roots to move through soil to new feeding sites (Castillo and Vovlas, 2007).
Reported host or associated host groups include corn, sweet potato, fruit trees, turf grass, pasture vegetation, and grasses (Castillo and Vovlas, 2007; Yu, 2008).
Ecophysiological Parameters:
Species of Pratylenchus are migratory endoparasites. They enter the root cortical tissues and migrate among cells, feeding on the contents of the cells and, consequently, killing them. The walls of dead cells of the root cortex break down and cavities form in the tissues. Damaged roots are often subject to invasion by secondary fungal and bacterial plant pathogens.
Plants with root damage from lesion nematodes have reuced capability of water and nutrient uptake and translocation,; they become stunted and chlorotic. Growth is poor, yields are reduced and plant death may occur.
Pratylenchus flakkensis is easily disseminated through movement of infested soil, rooted plants, nursery stock, turf, and contaminated equipment.
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
Castillo, P. and Vovlas, N. 2007. Pratylenchus (Nematoda: Pratylenchidae): diagnosis, biology, pathogenicity and management. Nematology Monographs and Perspectives 6. Brill, Leiden, The Netherlands.
Janssen, T., Karssen, G., Couvreur, M., Waeyenberge, L. and Bert, W. 2017. The pitfalls of molecular species identification: a case study within the genus Pratylenchus (Nematoda: Pratylenchidae). Nematology 19(10), 1179-1199.
Martin, H.J. 2026. California Pest Rating Proposal for Pratylenchus flakkensis, Root-lesion nematode, California Department of Food and Agriculture, Sacramento, California
Seinhorst, J.W. 1968. Three new Pratylenchus species with a discussion of the structure of the cephalic framework and of the Sspermatheca in this genus. Nematologica 14:497-510.
Subbotin, S.A., Ragsdale, E.J., Mullens, T., Roberts, P.A., Mundo-Ocampo, M. and Baldwin, J.G. 2008. A phylogenetic framework for root lesion nematodes of the genus Pratylenchus (Nematoda): evidence from 18S and D2-D3 expansion segments of 28S ribosomal RNA genes and morphological characters. Molecular Phylogenetics and Evolution 48, 491-505.
Yu, Q. 2008. Species of Pratylenchus (Nematoda: Pratylenchidae) in Canada. Canadian Journal of Plant Pathology 30, 575-584.