Rev: 12/18/2023
Tylenchida Tylenchina Criconematoidea Criconematidae Criconematinae
Criconemoides Taylor, 1936 Synonyms: Xenocriconemella (De Grisse and Loof, 1965) Criconemella (De Grisse and Loof, 1965) Madinema (Khan, Chawla and Saha, 1976) Seshadriella (Darekar and Khan, 1981) Neobakernema (Ebsary, 1981) Crossonemoides (Eroshenko, 1981) Macroposthonia (de Man, 1921)
Criconemoides is an agriculturally-important genus that has undergone several name changes over the years. Fortunately, the species names have remained stable. A considerable amount of the earlier literature on nematodes in the genus Criconemoides (Family: Criconematidae) refers to them by generic names that have since been synonymized, particularly Criconemoides, Macroposthonia and Criconemella. Maggenti (personal communication) argued to suppress the generic name Criconemella and to resurrect Criconemoides. That resurrection was accepted by some authors (Al Banna and Gardner, 1993), but more recently Luc proposed the name Criconemoides, which has gained fairly wide acceptance (e.g. Pinkerton et al., 1999; Carneiro et al., 1998).
A very large number of species has been described within the genus Criconemoides sensu lato. The genus was erected by Taylor (1936) to accommodate Criconematidae without cuticular extensions of the annules. When new genera were erected, the original name, Criconemoides, remained in question due to incomplete original description and lack of availability of type material. Subsequently, Criconemella was used but because there was no formal diagnosis of that genus, Brzeski et al. (2002a) resurrected the genus name Criconemoides. The name Criconemoides was proposed by Andrassy (1965) for species within Criconemoides with crenated margins of the annules. Through some convoluted history of generic name changes, well documented by Brzeski et al. (2002b), Criconemoides was resurrected as a genus name by Loof and de Grisse, 1989).
Powers et al. (2017) consider, based on 18S rDNA analysis, that Criconemoides should be recognized as a paraphyletic taxon separate from Mesocriconema. Further, that characters other than closed vulva and the lack of true submedian lobes are necessary to morphologically differentiate among Criconemoides lineages. They note that that the molecular-based relationship between several Criconemoides species and C. annulatus is distant, indicating that Criconemoides is a paraphyletic taxon.
Etymology:
Female: Body of variable length (0.20 to 1.00 mm); heavy annulation of cuticle - 200 or fewer, no spines, no extra cuticle; posterior edge smooth. Submedian lobes generally well-developed, but may be poorly developed and even absent in some species; separated or connected in different ways; first annules may be reduced or even divided into plates.
Vulval lips closely appressed (vulva "closed")
Females have long stylet and anchor-shaped knobs.
Head end rounded to conoid; generally four lateral lines, rarely three, caudal alae distinct, exceptionally absent (C. goodeyi).
Juveniles: Annuli smooth.
[Ref: Raski & Luc, 1987, and H. Ferris.]
Ring Nematode movement. Video Source: J.D. Eisenback, Nemapix.
Specimens of this interesting group of nematodes were rarely detected in soil samples, and were usually in low numbers, until the development of sugar flotation and centrifugation extraction techniques (Jenkins, 1964). Those techniques maximize recovery of "wide-bodied", slow-moving nematodes. They revealed that ring nematodes are very common, particularly in permanent crop, landscape and ornamental plantings. They can also be very abundant. Population levels of 50,000/l of soil have been recovered from around roots of peach trees (Jaffee and McInnis, 1991). Usually, diagnostic assessments of ring nematodes in soil samples are made only to the genus level. There may be several species associated with cultivated grapevines.
D-rated pests in California.
Ring nematodes feed ectoparasitically on root tips or along more mature roots. The nematodes are migratory unless soil pore space limits their movement. Adult stages of the larger ring nematode adults appear sedentary or stuck within their pore space as they develop to adult size.
Woody plants and turf are hosts for many species.
These nematodes exhibit characteristic slow, sluggish movement.
This group of nematodes is relatively unstudied on grape, however, among Prunus spp. it is known to seriously alter host physiology (Nyczespir and Wood, 1988).
Extraction poor except with sugar/centrifuge - then found frequently.
Pinkerton, J. N.; Forge, T. A.; Ivors, K. L.; Ingham, R. E.. 1999. Plant-parasitic nematodes associated with grapevines, Vitis vinifera, in Oregon vineyards. Journal of Nematology, 31:624-634.
Powers, T., Harris, T., Higgins, R., Mullin, P. Powers, K. 2017. An 18S rDNA Perspective on the Classification of Criconematoidea. J. Nematology 49:236-244.
Carneiro, Regina M.D.G.; Carvalho, Flavio L.C.; Kulczynski, Stela Maris. 1998. Plant selection to control Criconemoides xenoplax and Meloidogyne spp. with crop rotation. Nematologia Brasileira, 22:41-48.
Raski, D.J. and Luc, M. 1987. A reappraisal of Tylenchina (Nematoda) 10. The superfamily Criconematoidea Taylor, 1936. Revue de Nematologie 10:409-444.
Brzeski, M., Y.E. Choi and P.A.A. Loof. 2002a. Compendium of the genus Criconemoides Taylor, 1936 (Nematoda: Criconematidae). Nematology 4:325-339.
Brzeski, M., P.A.A. Loof and Y.E. Choi . 2002b. Compendium of the genus Criconemoides Andrassy, 1965 (Nematoda: Criconematidae). Nematology 4:341-360.
Loof, P.A.A and A. De Grisse. 1989. Taxonomic and nomenclatorial observations on the genus Criconemella De Grisse and Loof, 1965 sensu Luc and Raski, 1981. Med. Fac. Landn. Rijksuniv. Gent. 54:53-74.