Helicotylenchus

 

Contents

 

Rev 03/20/24

Spiral nematodes Classification Hosts
Morphology and Anatomy Life Cycle
Return to Helicotylenchus Menu Economic Importance Damage
Distribution Management
Return to Hoplolaimidae Menu Feeding  References
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Classification:

      Tylenchina
        Tylenchoidea
         Hoplolaimidae
          Hoplolaiminae

           Helicotylenchus Steiner, 1945

    Synonyms:

           Rotylenchoides (Whitehead, 1958)
           Zimmermannia (Shamsi, 1973)

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Morphology and Anatomy:

photo by Howard Ferris

 
Female: Body vermiform, spiral (when relaxed) to straight.

Labial region continuous to slightly offset, rounded or anteriorly flattened, generally annulated, but never longitudinally striated; anterior lip annule generally not divided into sectors, with elongate amphid apertures (SEM). Rarely faint or marked lip sectors are present.

Lateral field with four lines.

Phasmids small, near anus; cephalids and caudalid present.

Tail 1 to 2.5 body diameters long, typically more curved dorsally, with or without a terminal ventral process, sometimes rounded.

Stylet and labial framework average sized.

Dorsal esophageal gland opening (DEGO) from 6 to 16 um from stylet base.

Median bulb rounded with average-sized valve.

Glands overlap intestine dorsally and ventrally, all three glands of about the same length.

Two genital branches, the posterior one sometimes degenerated or reduced to a post-uterine sac. Epiptygma present, but folded inwards into the vagina. Vulval flaps present, inconspicuous.

Photograph from Ana Child, NREL, Colorado State University

Male: Slight secondary sexual dimorphism seen in smaller anterior end.

Caudal alae enveloping tail end.

Fortuner, et al.(1987), and H. Ferris.


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

Uzma et al (2015) list 230 nominal species in the genus Helicotylenchus as of 2015.

 
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Distribution:

 

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Economic Importance:

 D-rated pest in California Nematode Pest Rating System.

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Feeding:

Ectoparasites and endoparasites in root cortex.

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Hosts:

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

For Ecophysiological Parameters for this genus, click 
 
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Damage:

 

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Management:

 

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References:

Fortuner, Rev. Nematol. 10(2):219-232 (1987)

H. Ferris

Uzma, I., K. Nasira, K. Firoza and F. Shahina. 2015. Review of the genus Helicotylenchus Steiner, 1945 (Nematoda: Hoplolaimidae) with updated diagnostic compendium. Pakistan Journal of Nematology 33:115-160.

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Copyright 1999 by Howard Ferris.
Revised: March 20, 2024.