Paratylenchus neoamblycephalus  




Rev 02/13/2023

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           Paratylenchus neoamblycephalus Geraert, 1965

Nomenclature: Reuver, 1959 described a Paratylenchus species as P. amblycephalus. Hoever, subsequent sampling at the type l;ocality revealed a micture of two species, the species described by Reuver as P. amblycephalus (mainly) and P. projectus.  The specimen that Reuver designated as holotype for P. amblycephalus was actually P. projectus.  Geraert, 1965 selected a holotype from the main species present and designated it P. neoamblycephalus.  Consequently, the name P. amblycephalus is no longer valid (Raski, 1975)

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Morphology and Anatomy:

  Small plant-parasitic nematodes, 0.3mm long. 

Females:  Gravid female may swell anterior to vulva.

Strong stylet, usually about 36 µm.

Ovary single, outstretched.   

Males:  Reduced, with stylet reduced or absent, and probably do not feed. 

Often their starved bodies are marked by characteristic banding patterns as food reserves are depleted.

Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:

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California, Europe, Africa, North and South America, and Australia. 

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Economic Importance:

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Paratylenchus neoamblycephalus feeds singly or in groups of up to 15, especially at ruptures or where lateral roots emerge; heads remain in cortex
Nematodes were observed feeding ectoparasitically, but with heads embedded in roots as deep as the cortex. The nematodes cause small lesions (possibly caused by oxidation of phenolic compounds in roots) and lateral root death (Braun and Lownsbery, 1975)..        

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Rose, peach, apricot, apple, grape, Prunus (especially prunes), plum rootstocks - Myrobalan and Marianna, other herbaceous plants. 

Apple is a host in Europe and Australia, but not in California. 

This species is the most commonly occurring plant-parasitic nematode in California prune orchards. 

Non-hosts include fig and walnut.

For an extensive host range list for this species, click


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Life Cycle:

Ecophysiological Parameters:

For Ecophysiological Parameters for this species, click If species level data are not available, click for genus level parameters


Males and fourth-stage juveniles have no stylet and do not feed. Fourth stage juveniles of Paratylenchus are the survival stage (dauer) in some species.

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In greenhouse tests, top growth of plum reduced about 25% by high numbers of nematodes (Braun and Lownsbery), 1975.

Elimination of Paratylenchus neoamblvcephalus from soil by fumigation with 1,2-dibromoethane stimulated the growth of Myrobalan seedlings grown in it. Addition of a suspension of P. neoamblycephalus to Myrobalan seedlings inhibited their growth as compared to noninoculated controls.


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Usually not managed, nematicides have been used. 


Host Plant Resistance, Non-hosts and Crop Rotation alternatives:

For plants reported to have some level of resistance to this species, click


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Braun A.L. and Lownsbery, B.F. 1975. The pin nematode, Paratylenchus neamblycephalus, on myrobalan plum and other hosts J. Nematology 7:336-347.

Geareart, E. 1965. The genus Paratylenchus. Nematologica 11:301-334.

Raski, D.J. 1975. Revision of the Genus Paratylenchus Micoletzky, 1922 and Descriptions of New Species. Part II of Three parts. J. Nematology 7 :274-295.

Reuver I. 1959. Untersuchungen fiber Paratylenchus amblycephalus n. sp. (Nematoda, Criconematidae). Nematologica 4:3-15. 25. 



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Copyright © 1999 by Howard Ferris.
Revised: February 13, 2023.