Tylenchus emarginatus




Rev 11/19/2019

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Tylenchus emarginatus Cobb, 1893


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Morphology and Anatomy:

Key to the genera of the family Tylenchidae


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

Refer to subfamily diagnosis (Tylenchinae). 
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Commonly occurring in most soils.


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Economic Importance:

Probably fairly small. Most reports are about occurrence and abundance rather than documenting any effects on growth. 

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Ectoparasites of plant roots, root hairs, algae, etc. 

Yeates et al. (1993a) described Tylenchus as plant feeders (algal, lichen (algal or fungal component), or moss feeders that feed by piercing), or hyphal feeders.

Yeates et al. (1993b):  classified Tylenchus spp. as "plant associated", indicating that they were found in the rhizospheres of plants.


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Tylenchus emarginatus reported to feed and reproduce as a migratory ectoparasite on the roots of seven species* of conifer, but the nematode was unable to feed or reproduce on ten species of soil-borne fungi** (Thorne, 1961; Gowen, 1970).

* Picea abies, P. glauca, P. mariana, P. rubens, Pinus banksiana, P. sylvestris, P. resinosa, P. sitchensis

 ** Cylindrocarpon radicicola, Cylindrocladium scoparium, Rhizoctonia solani, Trichoderma lignorum, Zygorhynchus moelleri, Chaetomium sp., Fusarium sp., Pestolotia sp., Pythium sp., Sporobolomyces sp.

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

The generation time of T. emarginatus at 25C was 5-6 days.  Females did not produce eggs at temperatures > 30C or <10C.  Also eggs produced at favorable temperatures did not hatch at temperatures >30C or <10C.

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Relatively slight, small stylets penetrating only thin cell walls.  On water agar culture, T. emarginatus fed on root epidermal and root cap cells of sitka spruce (Picea sitchensis) without affecting root elongation or other obvious damage (Gowen, 1970).

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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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Gowen, S.R. 1970. Observations on the fecundity and longevity of Tylenchus emarginatus on sitka spruce seedlings at different temperatures. Nematologica 16:267-272.

Thorne, G. (1961), Tylenchinae, chapter 5 in: Principles of Nematology, McGraw-Hill Book Company Inc., New York - Toronto - London, 553 pp.

Yeates, G.W., Bongers, T., Goede, R.G.M. de, Freckman, D.W., Georgieva, S.S. (1993a), Feeding habits in soil nematode families and genera - an outline for soil ecologists, Journal of Nematology, 25 (3): 315-331.

Yeates, G.W., Wardle, D.A., Watson, R.N. (1993b), Relationships between nematodes, soil microbial biomass and weed-management strategies in maize and asparagus cropping systems, Soil Biology and Biochemistry, 25, 869-876.

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Copyright © 1999 by Howard Ferris.
Revised: November 19, 2019.