Nacobbus bolivianus




Rev 12/27/2013

False Root-knot Nematode Classification Hosts
Morphology and Anatomy Life Cycle
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Distribution Management
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    Nacobbus bolivianus Lordello, Zamith and Boock, 1961

    False Root-knot Nematode


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Morphology and Anatomy:

  Immature Females:
  • vermiform.
  • tylenchid stylet with well developed basal knobs;
  • head not off-set;
  • esophageal gland overlapping the intestine dorsally;
  • lateral field with four incisures;
  • monovarial
  • vulva close to the anus, sub-terminal
      Mature Females:

Saccate (0.8 to 1.4 mm long and 0.2 to 0.45 mm wide).

Nacobbus dorsalis differs from N. aberrans in the number of annules between vulva and anus (VA = 8-14 in N. dorsalis compared to VA = 15-24 in N. aberrans) and a more posterior vulval position in the immature females (94-97% compared to 91-94 %, respectively). Mature N. dorsalis females are rounder compared to the spindle-shaped N. aberrans females.

Posterior of female - vulva and anus (SEM):

 Photograph: I. Cid. del Prado

Drawing by Charles S. Papp, CDFA


Vermiform and of the same body length as females.

Caudal alae peloderan.

Spicules and gubernaculum.

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In California, this species of false root knot nematode is found occasionally in Kern, King, Los Angeles, Monterey, Riverside, and San Luis Obispo counties.  Mainly on plants not of agricultural importance.

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Economic Importance:

Mainly reported from non-agricultural plants, and quite rare.


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All juveniles are migratory endoparasites and penetrate plant root tips and/or axial roots.  

Mature females penetrate roots, become swollen and sedentary, cause formation of root galls and enlarged cells.

Nacobbus copy.jpg (41199 bytes)


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For an extensive list of host plant species and their susceptibility, copy the name

Nacobbus dorsalis

select Nemabase and paste the name in the Genus and species box



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Life Cycle:

Eggs are retained in the female body in N. dorsalis.

Life cycle is approximately 48 days at 25 C.

The nematode migrates through plant tissues as a juvenile; it initiates a gall and becomes sedentary as a young female.

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For a list of plant species or cultivars (if any) reported to be immune or to have some level of resistance to this nematode species, copy the name

Nacobbus dorsalis

select Nemabase Resistance Search and paste the name in the Genus and species box


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Manzanilla-López, R. H., M. A. Costilla, M. Doucet, J. Franco, R. N. Inserra, P. S. Lehman, I. Cid del Prado-Vera, R. M. Souza, and K. Evans. 2002. The genus Nacobbus
Thorne & Allen, 1944 (Nematoda:Pratylenchidae):Systematics, distribution, biology and management. Nematropica 32:149-227.

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Copyright © 1999 by Howard Ferris.
Revised: December 27, 2013 .