Rev 07/02/2024
Review general characteristics of the genus Meloidogyne.
Second-stage juvenile
Meloidogyne fallax is morphologically similar to the Columbia root-knot nematode (M. chitwoodi). It differs from M. chitwoodi in that males and females have longer stylets and that the J2 has a longer tail and hyaline portion.
The species can be separated by biochemical and molecular techniques: isozyme patterns esterase and malate dehydrogenase, fatty acid binding protein, and species-specific primers (Karssen, 1994; Peterson et al., 1997; Tastet et al., 2001).
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
Belgium, France, Germany and the Netherlands, Australia, New Zealnd, the United States and South Africa ( CAB International, 2001; Nobbs et al., 2001; Elling, 2013; Fourie et al., 2002).
Occurs in the U.S., reproted from golf course greens (Nischwitz et al., 2013).
Its most important agronomic host is potato, in which it can cause total yield losses due to quality defects and imposition of quarantines (Elling, 2013).
Sedentary endoparasite.
Feeding site establishment and development typical of genus.
Type host: tomato (Solanum lycopersicum)
Meloidogyne fallax has some hosts in common with M. chitwoodi: alfalfa (Medicago sativa), carrot (Daucus carota), potato (Solanum tuberosum), sugarbeet (Beta vulgaris), and tomato (Solanum lycopersicum).
Hosts not shared with M. chitwoodi include: hemerocallis (Hemerocallis sp.), Dicentra spectabilis, Oenothera erythrosepala, and Phacelia tenacetifolia.
Other differential hosts which are infected by M. chitwoodi but not by M. fallax are bean (Phaseolus vulgaris) and corn (Zea mays).
The following hosts of M. fallax but not reported for M. chitwoodi are artichoke (Cynara scolynus), lettuce (Lactuca sativa), and oyster plant (Scorzonera hispanica).
More information is needed on the host status of cereals to M. fallax.
Ecophysiological Parameters:
Haploid chromosome number n=18; reproduction is by facultative meiotic parthenogenesis. The egg nucleus undergoes a meiotic reduction division; one member of each pair of chromatids remains in a haploid nucleus and the other in a polar body. If fertilization by a male sperm occurs, the diploid number of chromosomes is restored. Otherwise the somatic number of chromosomes is restored by fusion of the egg pronucleus with the polar body from the reduction division (Subbotin et al., 2021; Triantaphyllou, 1985; Van der Beek & Karssen, 1997).
The nematodes cause small, round galls at root tips. Females produce egg masses protruding from the root surface (CAB International, 2001; EPPO, 2001).
Like M. chitwoodi, the major damage by M. fallax on potato tubers is a nematode-induced blemish which lowers or negates their marketability. Both species incite small galls, typically without secondary roots, and can lead to stunting and yellowing aboveground.In potato tubers, they cause numerous small pimple-like swellings
M. fallax is considered as closely related to M. chitwoodi; the two species can hybridize and produce viable F1 progeny under greenhouse conditions (Elling, 2013)
Dispersed through root material, soil debris and by poorly sanitized seed potatoes and bare root propagative material.
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
Quantitative PCR methods indicate potential for predicting yield loss in potato from M. fallax DNA measured in soil at planting and harvest (Hay et al., 2016).
CAB International. 2001. Meloidogyne fallax in Crop protection compendium, global module, 3rd editon. Wallingford, UK: CAB International.
Elling, A.A. 2013. Major Emerging Problems with Minor Meloidogyne Species. Phytopathology 103:1092-1102.
Epppo. 2001. Epppo PQR Database. Paris France.
Fourie, H., C. Zijlstra, A.H. McDonald and G. A. Venter. 2002. Advances in applied nematode research in South Africa after introduction of the SCAR-PCR technique for nematode identification. Nematology 4:160-161.
Hay, F.S., Kathy Ophel-Keller, Diana M. Hartley, and Sarah J. Pethybridge. 2016. Prediction of Potato Tuber Damage by Root-Knot Nematodes using Quantitative DNA Assay of Soil. Plant Disease 100:592-600.
Karssen, G. 1995. Morphological and biochemical differentiation in Meloidogyne chitwoodi populations in the Netherlands. Nematologica 41:314-315.
Nischwitz, N., A. Skantar, Z.A. Handoo, M.N. Hult, M.E. Schmitt, and M.A. McClure. 2013. Occurrence of Meloidogyne fallax in North America, and Molecular Characterization of M. fallax and M. minor from U.S. Golf Course Greens. Plant Disease 97:1424-1430.
Paterson D. J., and T. C. Vrain. 1996. Rapid identification of Meloidogyne chitwoodi, M. hapla, and M. fallax using PCR primers to amplify their ribosomal intergenic spacer. Fundamental and Applied Nematology 19:601-605.
Society of Nematologists Regulatory Committee, 2002.
Subbotin, S.A. Palomares-Rius, J.E., Castillo, P. 2021. Systematics of Root-knot Nematodes (Nematoda: Meloidogynidae). Nematology Monographs and Perspectives Vol 14: D.J. Hunt and R.N. Perry (eds) Brill, Leiden, The Netherlands 857p.
Tastet. C., F. Val, M. Lasage, L. Renault, L. Marche, M. Bpssis, and D. Mignieri. 2001. Application of a putative fatty acid binding protein to discriminate serologically the two European quarantine root-knot nematodes, Meloidogyne chitwoodi and M. fallax, from other Meloidogyne species. European Journal of Plant Pathology 107:821-832.
Triantaphyllou, A.C. 1985. Gametogenesis and the chromosomes of Meloidogune nataliei: not typical of other root-knot nematodes. J. Nematology 17:1-5.
Triantaphyllou, A.C. 1985. Cytogenetics, cytotaxonomy and phylogeny of root-knot nematodes. In Sasser, J.N. & Carter, C.C. (eds) An Advanced Treatiswe on Meloidogyne.Vol 1. Biology and Control.N.C. State Universty Graphics, Raleigh, N.C. USA.
Van der Beek, J.G and Karssen, G. 1997. Interspecific hybridization of meiotic parthenogenetic.Meloidogyne chitroodi and M. fallax. Phytopathology 87:1061-1066.