Evaluation of the Spatial Pattern of Stineerema riobravis in Corn Plots

Authors

  • H. E. Cabanillas
  • J. R. Raulston

Abstract

The vertical and horizontal spatial patterns of a naturally occurring population of the entomopathogenic nematode Steinernema riobravis (Rhabditida: Steinernematidae) were investigated in corn field soil by laboratory and field bioassays. This nematode appears to be endemic to the Lower Rio Grande Valley of Texas, where it was found parasitizing prepupae and pupae of both corn earworm, Helicoverpa zea, and fall armyworm, Spodopterafrugiperda (Lepidoptera: Noctuidae). Corn earworm prepupa was the bioassay host used to detect S. riobravis from soil in previously harvested corn plots. Steinernema riobravis occurred at soil depths of 5-30 cm. The maximum nematode density was in the upper 20 cm of soil, and the lowest density occurred at soil depth of 25-30 cm. The field and laboratory bioassays performed on the top 20 era of soil resulted in S. riobravis-infected corn earworm of 49 and 34%, respectively, whereas at 25-30 cm soil depths 11 and 4.5% of the H. zea were infected, respectively. The horizontal spatial pattern of this nematode was patchy or aggregated. Our study provides new information on the spatial pattern of S. riobravis in its natural habitat and indicates the need to augment its natural biocontrol efficacy. Key words: biological control, distribution, entomopathogenic nematode, nematode, spatial pattern, Steinernema riobravis.

Downloads

Published

1994-03-15

Issue

Vol. 26, No. 1 (March 1994)

Section

Articles

License

Copyright and Permissions

All material published by the Society of Nematologists (SON), except for papers prepared by United States and Canadian government employees, is copyrighted and protected under the U.S. copyright law. Under the Copyright Act of 1976, the term of copyright for materials registered by an organization is 75 years from the date first published. Before publishing any manuscript, SON requires that authors transfer full and complete ownership of any copyright to SON by signing a JON Page Charge/Copyright Form (.pdf). SON then registers the copyright. Subsequent use of published materials requires written permission from the SON and may be obtained by contacting the current Editor-in-Chief and state where and how the material will be used.

The author warrants that the article is an original work not published elsewhere in whole or in part, except in abstract form, and that the author has full power to make this grant. If portions of the article have been published previously, then the author warrants that permission has been obtained from the copyright holder and the author will submit a copy of the permission release with this copyright transfer form.

SON shall claim no proprietary right other than copyright. Authors and coauthors retain the right to revise, adapt, modify, or otherwise use all or part of the article in future works of the author(s), such as press releases, lectures, and reviews, provided that all such use is for the personal noncommercial benefit of the author(s). All patent rights are retained by the author(s).