A New Beneficial Nematode, Steinernema tophus from South Africa / by Ganpati Jagdale

A New Beneficial Nematode, Steinernema tophus

A new beneficial nematode, Steinernema tophus was collected from a vineyard located in Clanwilliam, South Africa (Cimen et al., 2014). Both  morphological and molecular characteristics of this newly isolated entomopatogenic nematode showed a close association with the ‘glaseri-group’ of Steinernema species.  Phylogenetic analyses showed that the Steinernema tophus is closely related to Steinernema khoisanae but its infective juveniles are wider and shorter than the infective juveniles of S. khoisanae. Also, the first -generation males S. tophus possess a conoid tail with a mucro whereas tail of S. khoisanae is digitated. When compared with the morphology of third-stage of S. tophus with the morphology of Steinernema innovation, excretory pores of S. tophus and S. innovation are located at average 88 and 90 micrometer from head region, respectively.  The tail of S. tophus was comparatively shorter (average 70 micrometer) than the S. innovation (average 76 micrometer). Since Steinernema tophus collected from a vineyard, it may be infecting and killing insect pests grapevines.  Like other beneficial entomopathogenic nematodes, it would be interested know which species of symbiotic bacteria are associated with Steinernema tophus.  The species specific symbiotic bacteria are generally carried by infective juveniles of entomopatogenic nematodes in their gut and used as weapon to kill their insect hosts after infection. For other comparative morphological and molecular characteristics among S. tophus, S. innovation and S. khoisana, read following research papers.

Research papers

  1. Cimen, H., Lee, M.M., Hatting, J., Hazir, S and Stock, S.P. 2014. Steinernema tophus sp n. (Nematoda: Steinernematidae), a new entomopathogenic nematode from South Africa. Zootaxa3821: 337-353.
  2. Cimen, H., Lee, M.M., Hatting, J., Hazir, S and Stock, S.P. 2014. Steinernema innovation n. sp. (Panagrolaimomorpha: Steinernematidae), a new entomopathogenic nematode from South Africa. Journal of Helminthology 1: 4.
  3. Nguyen, K.B., Malan, A., and Gozel, U. 2006. Steinernema khoisanae n. sp. (Rhabditidae: Steinernematidae), a new entomopathogenic nematode from South Africa. Nematology 8:157-175.