Rev 01/11/2024
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Tylenchida Tylenchina Criconematoidea Hemicycliophoridae Hemicycliophorinae Hemicycliophora de Man, 1921
Type species of the genus: Hemicycliophora typica de Man, 1921
Synonyms: Procriconema (Micoletzky, 1925) Colbranium (Andrassy, 1979) Aulosphora (Siddiqi, 1980) Loofia (Siddiqi, 1980)
There are at least 120 nominal species of Hemicycliophora Zhang et al., 2023
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Female: Extra cuticular layer always present, generally loose, never membranous.
Sloping stylet knobs.
Labial annules two (exceptionally three), not modified or separated (except in H. hesperis and H. truncata).
Vulva a transverse slit over half of body diameter long.
Vagina straight or curved, but not sigmoid.
Female tail:
Chitambar and Subbotin (2014) devided a pol;ytomous key for identification of Hemicycliophora species. That key was converted to a web-based system by Nguyen et al (2021) which is available online at http://nematodeidentification.mypressonline.com/ news/identification-key-for-hemicycliophora-spp/
Spicules arcuate, semi-circular, U- or hook-shaped.
Lips of cloaca forming a penial tube bearing a single hypoptygma at its tip.
Caudal alae 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)
H. Ferris
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).
D-rated pest in California Nematode Pest Rating System, except for H. arenaria which is A-rated.
Sheath nematodes are obligate ectoparasites of plant roots, their feeding incites development of root galls and growth retardation (Chitambar & Subbotin, 2014).
In the Northeast Polder in Holland, damage to carrot, bulbous iris, gladiolus and sugarbeet was caused by two species, Hemicycliophora conida and H. thienemanni.
Feed as migratory ectoparasites of higher plants, 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, Cooper et al., 1970; Van Gundy1957; 1959 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 difficult.
Applications of organic material to sandy soil inhibited population increase (Kuiper, 1977).
Nematicides are generally effective in the sandy soils in which these nematodes typically occur.
Chitambar, J.J. and Subbotin, S.A. 2014. Systematics of the sheath nematodes of the superfamily Hemicycliophoroidea. Nematology Monograph and Perspectives 10 (Series Editors: Hunt, D.J. & Perry, R.N.). Leiden, The Netherlands, Brill.
Cooper, A.F. Jr. Van Gundy, S.D., Stolzy, L.H. 1970. Nematode reproduction in environments of fluctuating aeration. J. Nematology 2: 182-188.
Kuiper, K. 1977. Introductie en vestiging van planteparasitaire aaltjes in nieuwe polders, in het bijzonder van Trichodorus teres. Wageningen Agricultural University dissertation no. 684.
Nguyen, H.T., Trinh, Q.P., Couvreur, M., Nguyen, T.D. & Bert, W. 2021. Description of Hemicycliophora cardamomi sp. n. (Nematoda: Hemicycliophoridae) associated with Amomum longiligulare T.L. Wu and a web-based key for the identification of Hemicycliophora spp. Journal of Helminthology 95, 1-11. DOI: 10.1017/S0022149X20000966
Raski, D.J. and Luc, M. 1987. A reappraisal of Tylenchina (Nematoda) 10. The superfamily Criconematoidea Taylor, 1936. Revue de Nematologie 10:409-444.
Timper, P. and Kaya, H. 1989. Role of the second-stage cuticle of entomogenous nematodes in preventing infection by nematophagous fungi. J. Invert. Pathology 34:314-421.
Van Gundy, S.D. 1957 The first report of a species of Hemicycliophora attacking citrus roots. Plent Disease Reporter 41:1016-1018.
Van Gundy, S.D. 1959. The life history of Hemicycliophora arenaria Raski (Nematoda: Criconematidae). Proc. Helminthol. Soc. Washington 26:67-72.
Zhang, C., Munawar, M., Castillo, P., Han, S., Zheng, J. 2023. Description of Hemicycliophora geraerti n. sp. (Tylenchida: Hemicycliophoridae) associated with runus persica L. from China. Nematology 25: 137-150.