Tylenchorhynchus cylindricus




Rev 04/03/2021

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Morphology and Anatomy Life Cycle
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Tylenchorhynchus cylindricus Cobb, 1913  

     Tylenchorhynchus dubius (Reynolds and Evans, 1935

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Morphology and Anatomy:

Female: Body straight to slightly arcuate in fixed specimens, tapering at both ends, 0.65-0.99 mm long..  

Annules distinct, coarse, 2 µm wide near midbody.

Lateral fields not areolated, about 1/4 as wide as body behind neck region, marked by 4 incisures.  

Deirids absent; phasmids prominent in both sexes, anterior to middle of tail, in neotype female on 5th and 8th annules behind anus.  

Lip region hemispherical, offset, exhibiting 5 (rarely 4 or 6) annules; labial sclerotization prominent towards basal plate and cheilostom.  

Stylet well developed, with large anteriorly-cupped basal knobs; tapering portion being non-tubular and needle-like in its anterior two-fifths.  

Orifice of dorsal esophageal gland about 2 µm from spear base.  

Median esophageal bulb large, oval; basal bulb elongate-pyriform, with intestine joining its base slightly ventrally; esophago-intestinal valve (cardiac valve) prominent.

Excretory pore near base of isthmus, just behind hemizonid which is 1-2 annules long.  

Sinuous, convoluted canals present in the intestinal region.

Ovaries outstretched with oocytes usually in single row.  

Spermathecae rounded, usually with sperm.   

Tail elongate-conoid, with unstriated, smoothly rounded distal end; intestine not extending into tail cavity.

Male: Body length 0.67-1.0 mm.


Spicules about 22 µm long, slightly arcuate, with large ventral flanges distally.

Gubernaculum 12 µm long, protrusible, its distal half enlarged with raised sides, proximal end anteriorly curved or crescent-shaped.

[Ref: CIH Descriptions of Plant-parasitic Nematodes, Set 1, No. 7 (1972)]




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

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Arid soils of Western U.S. on desert plants; Cathedral City, California.


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Economic Importance:

D-rated pests in California. 


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In cotton, nematodes feed on root tips and possibly along the side on young roots.

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Prunus in California; cotton in Arizona; citrus in Florida; pine in New Mexico; crested wheat grass (Agropyron cristatum) and juniper in Utah.

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
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In cotton, feeding causes stunting of top growth and reduction in root system in both greenhouse and field trials in Arizona.

Also reported to cause severe damage to crested wheat grass in areas of Utah.  

However, Riffle (1970) demonstrated that growth of seedling Pinus ponderosa parasitized by T. cylindricus under greenhouse conditions for 13 months was not significantly reduced.


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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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CIH Descriptions of Plant-parasitic Nematodes, Set 1, No. 7 (1972).

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Copyright © 1999 by Howard Ferris.
Revised: April 03, 2021.