Criconema

  

Contents

  

Rev: 11/06/2008

 Spine Nematode Classification Hosts
Morphology and Anatomy Life Cycle
Return to Criconema Menu Economic Importance Damage
Distribution Management
Return to Criconematidae Menu Feeding  References
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Classification:

      Tylenchida
      Tylenchina
        Criconematoidea
         Criconematidae
          Criconematinae
           Criconema (Hofmanner and Menzel, 1914)

    Synonyms:
      Lobocriconema (De Grisse and Loof, 1965)
      Nothocriconema (De Grisse and Loof, 1965)
      Merocriconema (Raski and Pinochet, 1976)
      Nenocriconema (Darekar and Khan, 1981)
      Nothletus (Ebsary, 1981)
      Nothocriconemella (Ebsary, 1981)
      Paracriconema (Ebsary, 1981)
      Amphisbaenema (Orton Williams, 1982)
      Cerchnotocriconema (Bernard, 1982)

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Morphology and Anatomy:

Criconema murrayi: scanning electron micrograph.

From Clark and Stone, 1976.

 Females: Body small to rather large (0.24 to 0.74 mm).  Short, plump, sluggish nematodes with spines and ornamentation on cuticle; 24-134 annulations.  

The various types of cuticular ornamentation are:
      1. finely crenate
      2. scale-like projections, if present, only on posterior part of body
      3. irregular, plate-like coverings on cuticle over entire body (C. paradoxiger, C. sheperdae) or on part of annules (lamellatum)
      4. ruffled, ribbon-like ornamentation encircling annule on anterior surface (C. giardi) or both anterior/posterior surfaces (psephinum)
      5. cuticular fringe extending from posterior margin of annules (C. brevicaudatum, C. giardi).

Labial region usually with six pseudo-lips, rounded and projecting forward from the first annule. Annuli of labial region smooth; usually with one annule wider and clearly set off from the next succeeding body annule; occasionally separation is not distinct and labial region appears to bear two annules.  

Stylet is 40 to 132 µm long.  

Vulva located on the 4th to the 21st annule from terminus, slit-like or completely closed by overhanging anterior lip.  

Tail is conoid-pointed to bluntly rounded. 
      
   

Males: Mostly unknown; have no stylet or caudal alae; have two to four lateral lines; bursa small, strongly reduced or lacking. 

Juveniles: Cuticle with scale-like cuticular appendages over entire body, usually with refractive elements or spine-like extensions at distal ends, arranged in 8 to 24 longitudinal rows.
      

[Ref: Raski & Luc, Rev. Nematol. 10(4):409-444 (1987), and H. Ferris.] 

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Distribution:

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Economic Importance:

D-rated pests in California.

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Feeding:

      Ring nematodes feed ectoparasitically on root tips or along more mature roots. The nematodes are migratory unless soil pore space limits their movement. 

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Hosts:

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Life Cycle:

Nematodes exhibit characteristic slow, sluggish movement.

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Damage:

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Management:

Extraction poor except with sugar/centrifuge.

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References:

Clark, S.A. and A.R. Stone, 1976. Nematologica 21:256-266.

Raski & Luc, 1987.  Rev. Nematol. 10(4):409-444.

H. Ferris 



 
 
Copyright © 1999 by Howard Ferris.
Revised: November 06, 2008.