Criconemoides

 

Contents

 

Rev: 04/05/2021

Ring Nematode Classification Hosts
Morphology and Anatomy Life Cycle
Return to Criconemoides Menu Economic Importance Damage
Distribution Management
Return to Criconematidae Menu Feeding References
    Go to Nemaplex Main Menu   Go to Dictionary of Terminology

Classification:

      Tylenchida
       Tylenchina
        Criconematoidea
         Criconematidae
          Criconematinae

           Criconemoides (Andrassy, 1965)

    Synonyms:
      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)

Criconemoides is a 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  refers to them by generic names that have since been synonymized, particularly  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).

 

Etymology:

 

Back to Top

Morphology and Anatomy:

Ring nematodes derive their name from their cuticle which is deeply striated.  The thickness of the cuticle may make it difficult to observe internal features.   Annuli are more or less retrorse, the first and second annuli separated from succeeding annuli, the presence of six pseudolips on the first annulus of which the two lateral pseudolips are  reduced to a connection with the four more developed and pronounced submedian lips; a closed vulva with a non-ornamented anterior lip; postvulval body short, conoid with a terminus rounded, conoid or acute.

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 (e.g. C. amorphus) first annule not retrorse, but more or less directed forward.

Vulval closed, anterior lip not overlapping 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; caudal alae distinct, exceptionally absent (C. goodeyi).

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)]

 

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

 

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

Distribution:

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.

Back to Top

Economic Importance:

D-rated pest in California Nematode Pest Rating System.

Back to Top

Feeding:

      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. 

Back to Top

Hosts:

      Woody plants and turf are hosts for many species.

For an extensive host range list for this genus, click
Back to Top

Life Cycle:

For Ecophysiological Parameters for this genus, click 
 

These nematodes exhibit characteristic slow, sluggish movement.

Back to Top

Damage:

In Prunus spp., this group of nematodes is known to seriously alter host physiology (Nyczespir and Wood, 1988). Feeding by M. xenoplax in grapevine roots results in diminution of non-structural carbohydrate reserves and in reduced accumulation of mineral nutrients (Schreiner et al., 2012),

Back to Top

Management:

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

Back to Top

References:

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 & Luc, Rev.  Nematol. 10:409-444 (1987)

Schreiner, R.P., Pinkerton, J.N., Zasada, I.A. 2012. Delayed response to ring nematode (Mesocriconema xenoplax) feeding on grape roots linked to vine carbohydrate reserves and nematode feeding pressure. Soil Biology and Biochemistry 43:89-97.

 

Back to Top

 
Copyright © 1999 by Howard Ferris.
Revised: April 05, 2021.