Paratylenchus projectus  




Rev 02/13/2023

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           Paratylenchus projectus

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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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East coast and midwestern U.S., Canada, Europe, New Zealand, and the Soviet Union. 

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Economic Importance:

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J2 and J3 feed; J4 has an incomplete stylet and molts to adult form after host stimulation. Nematodes insert stylet at or near base of root hairs and feed at one site for up to 6 days. 

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Cereals, grasses, ornamentals, celery, red clover, and cabbage.

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. 

J4 is the persistent stage - molt of the J4 is stimulated by host root diffusate, for example, carnation root diffusate.  The J4 do not molt to adults in water, but molt progressively over a 2 week period in carnation root diffusates (Rhoades and Linford, 1959).

In older pot cultures or field soils, the resistant J4 may be 80% of the population.

J4 distinguished from other stages by reduced or absent stylet and esophagus and accumulation of opaque granules in esophagus region (Rhoades and Linford, 1959).


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Control is difficult by crop rotation due to wide host range, or by fallow soil (J4 survives several years). 

Nematicides are not economical.


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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Rhoades, H.L. and M.B. Linford. 1959. Molting of preadult nematodes of the genus Paratylenchus stimulated by root diffusates.  Science 130: 1476-1477.

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