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Tylenchina Tylenchoidea Hoplolaimidae Hoplolaiminae Hoplolaimus seinhorsti Luc, 1958
Female: Length 1.0-1.48 mm.
Body cylindrical, slightly tapering towards front end; curved ventrally into an open circle when relaxed by gradual heating.
Lip region hemispherical, set off from body by a deep constriction, usually with 4 annules; as many as 6 annules may be present. Basal annule of lip region with 8 to 12 longitudinal striations.
Labial framework well-developed and sclerotized, displaying a yellow color, outer margins extending backward for a distance of 3.5 annules.
Lateral fields reduced, represented by a single incisure on body, but often indistinct.
Phasmids large, 4 or 5 µm in diameter, very refractive, anterior one at 26 to 44%, posterior one at 74 to 90% of body length from anterior end; anterior and posterior phasmid may be situated on either side of body.
Hemizonid 7 µm long, situated 5 to 21 annules posterior to excretory pore.
Hemizonion 5 to 10 annules posterior to hemizonid; hemizonid and hemizonion often appear as double structures at different levels in the body.
Spear massive, well-developed, 40 to 49 µm long, composed of two almost equal parts with large basal knobs; spear knobs with two blunt points on anterior margin separated by 2 or 3 small teeth, the latter often indistinct.
Orifice of dorsal esophageal gland 4 or 5 µm behind spear base.
Dorsal esophageal gland with 4 nuclei, overlaps the intestine dorsally; the 2 uni-nucleate subventral glands lie dorsolaterally and are variable in length.
Intestine does not overlap rectum.
Vulva at midbody or slightly posterior. Epiptygma usually single, anterior or posterior, but sometimes double.
Gonads paired, opposed and outstretched; no spermatheca observed.
Tail shorter than anal body diameter, rounded, with 10 to 17 annules; striations encircling the tip are sometimes irregular.
Africa, India, Philippines, Thailand, and Indonesia.
On cowpea, H. seinhorsti was found to be endoparasitic, mainly in the parenchymatous tissue of the root cortex and also in the cortex of root nodules.
In cotton roots, it was also found to be completely inside the cortical parenchyma (Luc, 1958).
Cotton, sugarcane, cowpea, sorghum, rice, corn, melon, many types of vegetables, coconut, and banana.
For an extensive list of host plant species and their susceptibility, copy the name
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Seeds of cowpea were germinated in a field plot in Nigeria naturally infested with H. seinhorsti. One week after germination, the roots contained all larval stages as well as eggs. Most nematodes were in the parenchymatous tissue of the root cortex, and browning of cells was evident immediately around individual nematodes.
The nematodes increased in the roots to a maximum of 1,110 individuals/root system after 5 weeks.
In the soil, the population increased from 100 to 3,800 individuals/liter of soil after 9 weeks (Bridge, 1973).
Endoparasitic migrations of nematodes can cause considerable mechanical damage to root cells.
Nematodes are mainly confined to lateral roots, and by the end of 9 weeks following germination of cowpea in field plot experiments, most lateral feeder roots were necrotic or missing.
Host Plant Resistance, Non-hosts and Crop Rotation alternatives:
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
select Nemabase Resistance Search and paste the name in the Genus and species box
CIH Descriptions of Plant-parasitic Nematodes, Set 6, No. 76 (1976)