Rev 12/16/2024
Chromadorea Rhabditida Tylenchina
Tylenchoidea Meloidogynidae Meloidogyninae
Meloidogyne graminis (Sledge & Golden, 1964) Whitehead, 1968
Synonyms:
Review general characteristics of the genus Meloidogyne.
Meloidogyne graminis: Perineal pattern
Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:
First reported as a parasite of turf grasses in Florida, USA and later from several US states and countries in South America, Europe and Asia (Subbotin et al., 2021)
First described as the cause of St. Augustine grass decline in Florida in 1959 by E. B. Sledge. It was initially assigned to a new genus and described as Hypsoperine graminis (Sledge and Golden, 1964) and later taransferred to the genus Meloidogyne (Whitehead, 1968).
C-rated pest in California Nematode Pest Rating System (Martin, 2024)
Sedentary endoparasite.
Feeding site establishment and development typical of genus.
Meloidogyne spp. are obligate, sedentary endoparasites that feed within host plant roots. The effect of root-knot nematodes on plants can be dramatic. As a result of their feeding, large galls or �knots� are formed on the root systems, which impairs the plant�s ability to take up water and nutrients from the soil (Chitambar et al., 2018).
The feeding site is a group of giant cells that develop in reponse to secretions of the nematode The giant cells undergo nuclear division without cell division so that the cells become multinucleate and enlarge in the process. are significant nutrient sinks, producing large amounts of proteins and carbohydrates that provide resouces for the developing nematodes. Plant growth regulators produced during nematode feeding play an importatnt role in the increase in cell size and nuclear division. Root cells adjacent to the giant cells enlarge and divide rapidly, resulting in hyperplasia and gall formation.
Once a juvenile establishes a feeding site, it undergoes three more molts to become an adult which, if a female, remains permanently within the plant root, exuding her eggs out into and egg mass on the root surface (Perry and Moens, 2013; Martin, 2024).
Type Host: St. Augustine Grass (Stenotaphrum secundatum) and a large number of other grasses.
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). The nematode is considered to reproduce sexually (amphimixis) when males are present, and by meiotic parthenogenesis when males are absent (Triantaphyllou, 1973; Martin, 2024).
The first stage juvenile develops within the egg and molts to develop into the second stage. The second-stage juveniles (J2) are the infective stage. They hatch from eggs and migrate in rhizosphere soil to host roots, either the same roots they were originally associated with or other nearby host roots. The J2s penetrate the host roots and establish a specialized feeding site that is formed at the head end of the nematode in response to its feeding. They become sedentary while feeding at the specialized site, increasing in size and undergoing two more molts and non-feeding stages before developing into mature adult females or vermiform males and completing the life cycle (Martin, 2024). Males leave the root and apparently no longer feed.
Damaging to turf (Azevedo de Oliveira et al., 2018; Esser and Langdon, 1965; McClure et al., 2012).
Roots darken, the root cortex splits and the stele becomes exposed, dry, and brittle. Over time the cortex sloughs away. Gallis appear as elongated swellings on infected adventitious roots; they develop as cluster of three to four swellings.. Root elongation is impaired and lateral root development is suppressed. Infected root tips can curve into a �J� shape.
The above-ground growth of the plants becomes chlorotic and stunted. Plants will eventually die (Grisham et al., 1974; MacGowan, 1984; Martin, 2024).
Resistance
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
Probably readily transmitted to new locations in infetsed turf and sod.
Azevedo de Oliveira, S., Oliveira, C.M.G.D., Maleita, C.M.N., Silva, M.D.F.A., Abrantes, I.M.D.O. and Wilcken, S.R.S., 2018. First report of Meloidogyne graminis on golf courses turfgrass in Brazil. Plos one, 13(2), p.e0192397.
Chitambar, J. J., Westerdahl, B. B., and Subbotin, S. A. 2018. Plant Parasitic Nematodes in California Agriculture. In Subbotin, S., Chitambar J., (eds) Plant Parasitic Nematodes in Sustainable Agriculture of North America. Sustainability in Plant and Crop Protection. Springer, Cham
Esser, R. P., and Langdon, K. R. 1965. Pseudo-root-knot nematode of turf. Pages 67-69 in: Fla. Dept. Agric and Consumer Services, Div. Plant Ind. Twenty-fifth Biennial Report July 1, 1962 -June 30, 1964
Grisham, M.P., Dale, J.L., and Riggs, R.D., 1974. Meloidogyne graminis and Meloidogyne spp. on zoysia; infection, reproduction, disease development, and control. Phytopathology, 64(12), pp.1485-1489.
MacGowan, J. B. 1984. Meloidogyne graminis, a root-knot nematode of grass. Fla. Dep. Agric and Consumer Serv. Division of Plant Industry. Nematology Circular No. 197.
Martin, H.J. 2024. California Pest Rating Proposal for Meloidogyne graminis (Sledge & Golden) Whitehead 1968 Grass root-knot nematode. California Department of Food and Agriculture, Sacramento, Califronia, USA
McClure, M.A., Nischwitz, C., Skantar, A.M., Schmitt, M.E. and Subbotin, S.A., 2012. Root-knot nematodes in golf course greens of the western United States. Plant disease, 96(5), pp.635-647.
Sledge, E.B. and Golden, A.M., 1964. Hypsoperine graminis (Nematoda: Heteroderidae), a new genus and species of plant-parasitic nematode. Proceedings of the Helminthological Society of Washington, 31, pp.83-88.
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.
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.
Whitehead, A.G. 1968. Taxonomy of Meloidogyne (Nematodea: Heteroderidae) with descriptions of four new species. Trans. Zoological Soc. London. 31: 263-401
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