Gracilacus latescens




Rev 02/13/2023

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           Gracilacus latescens Raski, 1976

      Paratylenchus latescens

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Morphology and Anatomy:


Female:  Small, under 0.5 mm, vermiform or swollen in prevulval region.

Labial framework weakly sclerotized.



Juvenile: Resembling female.  

Stylet generally present, well developed.

[Ref: Raski & Luc (1987), and H. Ferris.]  


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

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Florida and?.

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Economic Importance:

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Young, vermiform, female inserts its long stylet into root tissues and remains attached to the root surface by the stylet. Nematode feeds in epidermal, cortical parenchyma and sclerenchyma cells. Feeding induces cell wall thickening.

Stylet penetrates through 3-4 layers of cells and is encased in an electron-dense, cytoplasmic feeding tube. The feeding tube appears to attach the nematode to the root.

Continuous feeding results in that extends into endodermis, pericycle, phloem and vascular parenchyma cells. Discrete cells with hypertrophied nuclei and nucleoli, and dense, granular cytoplasm are visible in the syncytium. Endodermal cells incorporated in the syncytium lose cell wall thickening.

Troccoli et al (2002), Inserra et al (2003)

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Timber bamboo (Phyllostachys bambusoides) roots in central Florida.

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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

Young, vermiform, female inserts its long stylet into root tissues and remains attached to the root surface by the stylet. Female body swells as gonads mature. Eggs are deposited in a gelatinous matrix which surrounds the female, eggs and and newly hatched J2s.

J2 stage probably does not feed. Third (J3) and fourth stage juveniles (J4) are inactive, coiled, and lack a stylet; they also do not feed.  They retain the cuticle of the previous stage.  They develop without feeding into motile, vermiform, males and vermiform females, still surrounded by juvenile stage cuticles. (Troccoli et al, 2002).


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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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Inserra RN, Achor D, Duncan LW, Troccoli A. 2003. Ultrastructure of the attachment and feeding sites of Gracilacus latescens Raski, 1976 in timber bamboo roots and selected anatomical details of the female stylet. Nematology 5:307-312.

Raski, D.J. 1976. Revision of the Genus Paratylenchus Micoletzky, 1922 and Descriptions of New Species. Part III of Three parts--Gracilacus. J. Nematology 8:97-115.

Troccoli A, Vovlas N, Inserra RN. 2002. Parasitism of timber bamboo roots by Gracilacus latescens Raski, 1976 and morpho-biological notes on mature and immature life stages. Nematropica 32: 87-102.

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