Meloidogyne mali

Apple Root-knot Nematode




Rev 11/07/2023

  Classification Hosts
Morphology and Anatomy Life Cycle
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        Meloidogyne mali Itoh, Ohshima & Ichinoche, 1969


Melodogyne ulmi Palmisano & Ambrogioni, 2000

A nematode parasitizing elms (Ulmus sp.) in Italy was described as Meloidogyne ulmi (Palmisano and Ambrogioni, 2000). Due to overlap of many of the morphological characters, M. ulmi was synonymized with M. mali. Besides their morphological similarities, the nematodes have hosts in common and have biochemical and molecular similarities by Ahmed et al. (2013).

Review general characteristics of the genus Meloidogyne.

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Morphology and Anatomy:

  Meloidogune mali differs from M. suginamiensis  in having a female perineal pattern with oval outline and  smooth striae vesrus a slightly squarish outline with wavy striae . The species also differ in characteristics of the J2 and males.


Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:

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Reported from Asia: Japan, Republic of Korea. Europe: Belgium, France, Italy, Netherlands, United Kingdom (EPPO, 2023).

 Meloidogyne mali has so far been reported from one location in the United States. In 2016, Eisenback et al. reported that a root sample from a declining hedge of Euonymus kiautschovicus at a private residence in Harrison, NY, showed roots disfigured with swellings and galls and contained adult females. Molecular analyses indicated similarities of 96-98% with international isolates of M. mali.

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Economic Importance:

A-rated pest in California per CDFA (Scheck, 2023).

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Sedentary endoparasite.

As in other species of this genus, second stage juveniles (J2s) penetrate the host roots and establish a specialized feeding of multinucleate giant cells . Giant cells deleop by nuclear divison without cell divisio (karyokinesis without cytokinesis), incited by secretions form the nematode (see genus decription).

Giant cells are significant nutrient sinks, producing large amounts of proteins as resources for the nematode. . Cells neighboring the giant cells divide rapidly, enlarging the surrounding tissues (hyperplasia) and causing the formation of characteristic root galls.. Root cells next to the giant cells enlarge and divide rapidly, resulting in gall formation. Usually cellulase activity, thought to be from the nematode rectal glands, disintegratesw celld between the posterior of the nematode and the surface of the gall. The femaleexudes a gelatinous matris into which she depositis several hundred eggs.  The gelatinous egg masses are mainly on the surafec of the gall.


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Type Host: Apple (Malus prunifolia)

.Reported primarily from woody perennial including fruit and nut trees, flowering trees, shade trees, woody shrubs, vines, brambles, vegetables, row crops, flowers, weedy plants, and ferns.


For an extensive host range list for this species, click
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Life Cycle:

Chromosome number 2n=22.  In most species of Meloidogyne, reproduction is by parthenogenesis  Usually males are not very abundant except in the relatively few species where reproduction id by anmphimixis.  However, in M. mali, males are relatively abundant and the species has been found to reproduce by amphimixis (Janssen et al., 2017; Subbotin et al., 2021; Triantaphyllou, 1985).

Invading J2s become sedentary while feeding, increase at the giand cell system, increase size, and undergo two more molts and non-feeding stages before developing into mature adult females or vermiform males and completing the life cycle.

In some Meloidogyne spp., under conditions of stress, includingpoor plant growth and lack of resources for the sedentary feeding stages, J2s develop into males rather than females.  Since males leave the root withour feeding, that reduces the competitive stress for resources among feeding stages.

Ecophysiological Parameters:

For Ecophysiological Parameters for this species, click If species level data are not available, click for genus level parameters


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Meloidogyne mali is described as one of the most damaging nematodes for apples in Northern Japan, causing stunting and severe decline of trees in orchards (Itoh et al., 1969; Nyczepir and Halbrendt, 1993).

Meloidogyne mali, like other root-knot nematodes, induces galls which may be up to 0.5 cm in diameter. Galls can become largere on older plants, 1-2 cm in diameter. Symptoms in trees only appear when the trees are heavily infested and include early leaf fall and reduced growth (Subbotin et al., 2021).

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Prevention of Spread: Since many fruit trees and vines are grown on vines propagated in nurseries, the transport of rooted material is a very effective means of spreading the nematode to uninfested fields and new locations.  Similarly, shared or rented equipment used for soil tillage or harvesing, or the movement of workers among fields, increases the probability of spread.


Host Plant Resistance, Non-hosts and Crop Rotation alternatives:

For plants reported to have some level of resistance to this species, click
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Ahmed, M., van de Vossenberg, B.T., Cornelisse, C. and Karssen, G., 2013. On the species status of the rootknot nematode Meloidogyne ulmi Palmisano & Ambrogioni, 2000 (Nematoda, Meloidogynidae). ZooKeys, 362:.1.

Eisenback, J.D., L. S. Graney, and P. Vieira. 2017. First Report of the Apple Root-Knot Nematode (Meloidogyne mali) in North America, Found Parasitizing Euonymus in New York. Plant Disease 101:510.

EPPO Database. Accessed 8/17/23.

Itoh, Y., Ohshima, Y. and Icchinohe, M.1969. A root-knot nematode, n. sp. on apple trees from Japan (Tylenchida: Heteroderidae). Appl. Ent. Zool. 4:194-202

Janssen, T., Karssen, G., Topalovic, O., Coyne, D., Bert, W. 2017. Integrative taxonomy of root-knot nematodes reveals multiple independent origins of mititic parthenogenesis.  PloS ONE 12: e0172190.

Nyczepir, A.P. and Halbrendt, J.M., 1993. Nematode pests of deciduous fruit and nut trees. Plant parasitic nematodes in temperate agriculture., pp.381-425.

Palmisano, A.M. and Ambrogioni, L., 2000. Meloidogyne ulmi sp. n., a root-knot nematode from elm. Nematologia Mediterranea, pp.279-293.

Perry, R.N. and Moens, M. eds., 2013. Plant nematology 2nd Ed. Cabi.

Prior, T., Tozer, H., Yale, R., Jones, E.P., Lawson, R., Jutson, L., Correia, M., Stubbs, J., Hockland, S. and Karssen, G., 2019. First report of Meloidogyne mali causing root galling to elm trees in the UK. New Disease Reports, 39, pp.10-10.

Scheck, H.J. 2023. California Pest Rating Proposal forMeloidogyne mali Itoh, Oshima & Ichinohe 1969, apple root-knot nematode. California Department of Food and Agriculture Sacramento, California, USA.\

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.

Toida, Y. 1991. Mulberry damages caused by a root-knot nematode, Meloidogyne mali indigenous to Japan. Japan Agricultural Research Quarterly 24(4), 300-305.idogyne ulmi Palmisano & Ambrogioni, 2000 (Nematoda, Meloidogynidae). ZooKeys 362:1-27

Toida, Y. and Yaegashi, Y. 1984. Description of Meloidogyne suginamiensis n. sp.(Nematoda: Meloidogynidae) from mulberry in Japan. Japanese J. Nemwatology 14: \49-57.

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.

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Copyright © 1999 by Howard Ferris.
Revised: November 07, 2023.