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Hemicycliophora de Man, 1921
Procriconema (Micoletzky, 1925)
Colbranium (Andrassy, 1979)
Aulosphora (Siddiqi, 1980)
Loofia (Siddiqi, 1980)
There are at least 25 species of Hemicycliophora.
Female: Extra cuticular layer always present, generally
loose, never membranous.
Sloping stylet knobs.
two (exceptionally three), not modified or separated (except in H. hesperis
and H. truncata).
Vulva a transverse slit over half of body diameter
Vagina straight or curved, but not sigmoid.
arcuate, semi-circular, U- or hook-shaped.
Lips of cloaca forming a penial tube bearing a single hypoptygma at
covering less than one-third of the tail.
Tail longer than that of female.
Males are rare in many populations. They have a degenerate esophagus and no stylet.
Juvenile: Fourth-stage male juvenile without stylet.
Ref: Raski and Luc (1987)
Photomicrographs by I.A. Zasada
Nematode common in sandy soils.
One of the first nematodes to cause damage on the new polders reclaimed from
the former Zuiderzee in Holland. Initially the newly-reclaimed soil was free of
plant-parasitic nematodes. In the Northeast Polder, reclaimed in
1942, infestations were already apparent by 1949 (Kuiper, 1977).
in California Nematode Pest Rating System, except for
H. arenaria which is
In the Northeast Polder in Holland, damage to carrot, bulbous iris, gladiolus
and sugarbeet was caused by two species, Hemicycliophora conida and H.
Feed as ectoparasites, usually near root tip.
The adaptive significance of the sheath is
uncertain, although it may provide protection from predaceous fungi as reported
for the entomopathogenic nematode, Heterorhabditis spp. (Order: Rhabditida, Family:
Rhabditidae) (Timper and Kaya, 1989).
Hemicycliophora spp. sometimes
appear intolerant of low aeration associated with wet soil (e.g.
H. arenaria in citrus, Van Gundy et al). In other cases, they
are found in very wet, and rather anaerobic, sandy soils along stream banks.
Where two species were present in Holland, H. conida was mostly found
in the topsoil while H. thienemanni dominated the deeper layers.
Population levels of both species were greatest just below the tilled layer.
Experiments revealed differences between the species in relation to soil
moisture (Kuiper, 1977).
Usually causes root-tip swelling and stunted root/plant growth.
Hemicycliophora spp., occasionally occur in vineyard
sites, especially in wetter areas. Although they parasitize grapevines, and are
usually root tip feeders, the amount of damage they cause is unknown. They do,
however, cause substantial damage in citrus (Van
Gundy and Rackham, 1961).
See information on individual species.
Hemicycliophora spp. tend to be polyphagous so that crop rotation is
Applications of organic material to sandy soil inhibited population increase
Nematicides are generally effective in the sandy soils in which these
nematodes typically occur.
Raski and Luc, Rev. Nematol. 10(4):409-444 (1987)
Kuiper, K. 1977. Introductie en vestiging van planteparasitaire
aaltjes in nieuwe polders, in het bijzonder van Trichodorus teres.
Wageningen Agricultural University dissertation no. 684.