Malenchus

  

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Rev 09/14/20
  Classification Hosts
Morphology and Anatomy Life Cycle
Return to Malenchus Menu Economic Importance Damage
Distribution Management
Return to Tylenchidae Menu Feeding  References
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Classification:

      Tylenchida
      Tylenchina
       Tylenchoidea
        Tylenchidae
         Tylenchinae

           Malenchus Andrassy, 1968


    Synonyms:
      Neomalenchus Siddiqi, 1979

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Morphology and Anatomy:

Besides the coarsely annulated cuticle and markedly tapering body posterior to the vulva, the offset lateral region with small sub-ridges, pouch-like amphidial fovea and vagina with swollen wall are considered important defining characters of the genus (Qing and Bert, 2017).

 
  • Body size  250-900µm.
  • Body dorsoventrally compressed an lip region somewhat flattened.
  • Body tapers posterior to vulva so that abd is usually about 50% of vbd.
  • Cuticle thick with prominent striations. The striations have inner folds that may harbor microorganisms and fungi.
  • Lateral field with two to >12 incisures.
  • Head generally elevated, not or slightly offset; usually no distinct oral disc.
  • Amphid openings variously shaped (but geenerally fovea are pouch-like.
  • Stylet small to very small, usually with knobs that are flattened and sloping backwards; cone 1/3 to 1/2 as long as shaft..
  • Metacorpus weak to moderate.
  • Female genital tract monovarial, prodelphic, short with only three or four cells in each of the four rows of the crustaformeria part of the uterus, spermatheca offset or not.
  • Vulva sunken, a transverse slit with lateral flaps; vagina with swollen wall in proximal or middle part.
  • Tail elongated.
  • Male generally less frequent than female.
  • Male bursa adanal, spicules curved ventrally, gubernaulum small.

Ref: Geraert & Raski, (1987); Qing and Bert (2017); Qing et al. (2016).

Two subgenera may be considered: Malenchus (Malenchus) Andr�ssy, 1968 and Malenchus (Telomalenchus) Siddiqi, 2000. Subgenus Malenchus is characterized by a simple lateral field with around 12 or mode very fine lines only vivible by SEM (Qing et al. 2017),and amphidial openings anteriorly wider sinusoid slit, about three to five cephalic annuli long. Subgenus Telomalenchus has a lateral field with three or five bands and amphidial slits that are short and curved (Siddiqi 2000; Geraert 2008). The lateral dikes or flaps of the vulva also differs between the two subgenera (Geraert 2008).
 
Body size range for the species of this genus in the database - Click:
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Distribution:

Malenchus is the second-most speciose genus of the Tylenchidae amd is cosmopolitan in distribution (Qing and Bert, 2017; Qing et al., 2016).

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Economic Importance:

 

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Feeding:

Unknown, often found associated with decomposing litter, but under and around plants.  M. bryophilus feeds on som plant roots (Khera and Zuckerman, 1963).

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Hosts:

Malenchus bryophilus feeds on cabbage roots for a long period and on dill and alfalfa for a maximum period of 2.5 minutes. It does not feed on broccoli, cauliflower, kohlrabi, radish, carrot, tomato, lettuce, beet, rye grass and marigold (Khera and Zuckermann, 1963).

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:

Geraert, E. 2008. The Tylenchidae of the World. Identification of the Family Tylenchidae (Nematoda). Ghent, Belgium, Akademia Press

Geraert & Raski, (1987) Rev. Nematol. 10(2):143-161.

Khera, S., Zuckermann, B.M. (1963). In vitro studies of host-parasite relationships of some plant-parasitic nematodes, Nematologica, 9, 1-6.

Pedram, M., Soleymanzadeh, M., Pourjam, E., Mobasserim, M. 2018. Observations on Malenchus geraerti n. sp. (Rhabditida: Tylenchidae), a morphological and molecular phylogenetic study. Zootaxa 4369:406-418.

Qing, X., S�nchez-Monge, A., Janssen, T., Couvreur, M. and Bert, W. 2016. Description of Malenchus sexlineatus n. sp., new records of three known species of Malenchus Andr�ssy, 1968 (Nematoda: Tylenchidae) and notes on amphidial aperture development. Nematology 18:155-174.

Qing, X., Bert, W. 2017. Redefinition of Genus Malenchus Andrassy, 1968 (Tylenchomorpha: Tylenchidae) with Additional Data on Ecology. J. Nematology 49:189-206.

Siddiqi, M.R. 2000. Tylenchida. Parasites of Plants and Insects, 2nd edition. Wallingford, UK, CAB International,

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Copyright © 1999 by Howard Ferris.
Revised: September 14, 2020.