Rev: 04/04/2021

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           Mesocriconema (Andrassy, 1965)

      Xenocriconemella (De Grisse and Loof, 1965)      
      Criconemella (De Grisse and Loof, 1965)
      Madinema (Khan, Chawla and Saha, 1976)
      Seshadriella (Darekar and Khan, 1981)
      Neobakernema (Ebsary, 1981)
      Crossonemoides (Eroshenko, 1981)
      Criconemoides (Taylor, 1936)
      Macroposthonia (de Man, 1921)

Mesocriconema is an agriculturally-important genus that has undergone several name changes over the years. Fortunately, the species names have remained stable. A considerable amount of the earlier literature on nematodes in the genus Mesocriconema (Family: Criconematidae) refers to them by generic names that have since been synonymized, particularly Criconemoides, Macroposthonia and CriconemellaMaggenti (personal communication) argued to suppress the generic name Criconemella and to resurrect Criconemoides. That resurrection was accepted by some authors (Al Banna and Gardner, 1993), but more Loof and de Grisse (1989) proposed the name Criconemoides, which gained fairly wide acceptance (e.g. Pinkerton et al., 1999; Carneiro et al., 1998).  However, Mesocriconema was proposed by Andrassy (1965) for species with crenate margins of the retrorse annuli. 

A very large number of species has been described within the genus Criconemoides sensu lato. The genus was erected by Taylor (1936) to accommodate Criconematidae without cuticular extensions (crenations) of the annules.  When new genera were erected, the original name, Criconemoides, remained in question due to incomplete original description and lack of availability of type material.  Subsequently, Criconemella was used but because there was no formal diagnosis of that genus, Brzeski et al. (2002a) resurrected the genus name Criconemoides.  The name Mesocriconema was proposed by Andrassy (1965) for species with crenated margins of the annules.  Through some convoluted history of generic name changes, well documented by Brzeski et al. (2002b), Criconemoides was resurrected as a genus name by Loof and de Grisse, (1989).

The taxonomic status and species composition of the genera Criconemoides Tylor 1936 and Mesocriconema Andrassy, 1965 continues to be controversial.

The general criteria for distinguishing between the two genera are:

Ongoing molecular characterizations are expected to clarify the distinctions or lack thereof.

References: Cordero et al. (2012), Geraert (2010).



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Morphology and Anatomy:

Ring nematodes derive their name from their cuticle which is deeply striated. The cuticle has retrorse annuli with margin smooth or crenate; the first annulus is seldom separated from the second; the four submedian lips are reduced and each has a prominent outgrowth or submedian lobe; the vulva is open, often with the anterior lip ornamented; the postvulval body short with the terminus round or truncate.The thickness of the cuticle may make it difficult to observe internal features. 

Female: Body of variable length (0.3 to 0.6 mm); heavy annulation of cuticle - 200 or fewer, no spines, no extra cuticle; posterior edge smooth, uneven or crenate. Submedian lobes of lips generally well-developed, but may be poorly developed and even absent in some species; separated or connected in different ways.

First body annule may be reduced.  Second annule usually wider than first. In some species (M. axeste, M. citricola) first annule not retrorse, but more or less directed forward.

Vulval lips widely separated (vulva "open"); anterior lip may be ornamented.

Females have long stylet and anchor-shaped knobs.

Males: Rare; have no stylet or bursa; have straight spicule.

Head end rounded to conoid; generally four lateral lines, rarely three, exceptionally two (M. oostenbrinski); caudal alae distinct.

Juveniles: Annuli smooth to crenate, no rows of scales.

[Ref: Raski & Luc, Rev. Nematol. 10(4):409-444 (1987), and H. Ferris; Cordero et al. (2012), Geraert (2010)]

Body size range for the species of this genus in the database - Click:

Ring Nematode movement (pass mouse over thumbnail picture).  Video Source: J.D. Eisenback, Nemapix.

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Specimens of this interesting group of nematodes were rarely detected in soil samples, and were usually in low numbers, until the development of sugar flotation and centrifugation extraction techniques (Jenkins, 1964). Those techniques maximize recovery of "wide-bodied", slow-moving nematodes. They revealed that ring nematodes are very common, particularly in permanent crop, landscape and ornamental plantings. They can also be very abundant. Population levels of 50,000/l of soil have been recovered from around roots of peach trees (Jaffee and McInnis, 1991).

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Economic Importance:

D-rated pests in California.

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      Ring nematodes feed ectoparasitically on root tips or along more mature roots. The nematodes are migratory unless soil pore space limits their movement. Adult stages of the larger ring nematode adults appear sedentary or stuck within their pore space as they develop to adult size. 

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      Woody plants and turf are hosts for many species.

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

For Ecophysiological Parameters for this genus, click 

Nematodes exhibit characteristic slow, sluggish movement.

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This group of nematodes is relatively unstudied on grape, however, among Prunus spp. it is known to seriously alter host physiology (Nyczespir and Wood, 1988).

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Extraction poor except with sugar/centrifuge - then found frequently.

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Pinkerton, J. N.; Forge, T. A.; Ivors, K. L.; Ingham, R. E..  1999. Plant-parasitic nematodes associated with grapevines, Vitis vinifera, in Oregon vineyards. Journal of Nematology, 31:624-634.

Brzeski, M., Y.E. Choi and P.A.A. Loof. 2002a.  Compendium of the genus Criconemoides Taylor, 1936 (Nematoda: Criconematidae).  Nematology 4:325-339.

Brzeski, M., P.A.A. Loof and Y.E. Choi . 2002b.  Compendium of the genus Mesocriconema Andrássy, 1965 (Nematoda: Criconematidae).  Nematology 4:341-360.

Cordero, M. A. Robert T. Robbins, Allen L. Szalanski. 2012. Taxonomic and Molecular Identification of Mesocriconema and Criconemoides Species (Nematoda: Criconematidae). J. Nematology 44: 399-426.

Geraert, E. 2010. The Criconematidae of the World: Identification of the Family Criconematidae. Academia Press, Gent. 615p.

Loof, P.A.A and A. De Grisse. 1989. Taxonomic and nomenclatorial observations on the genus Criconemella De Grisse and Loof, 1965 sensu Luc and Raski, 1981. Med. Fac. Landn. Rijksuniv. Gent. 54:53-74.

Raski, D.J. and Luc, M. 1987. A reappraisal of Tylenchina (Nemata) 10. The superfamily Criconemaroidea Taylor, 1936. Rev. Nemarol. 10:409-444.


Copyright © 1999 by Howard Ferris.
Revised: April 04, 2021.