Spinosad is a relatively new insecticide with a unique mode of action that is being evaluated for control of larval mosquitoes. Whereas a number of toxicological studies have measured effects of spinosad on various mammals, fish, birds, and terrestrial arthropods, fewer studies have been conducted on the effects of spinosad on non-target aquatic insect species. Such studies are important as these species might be found in the same environments as mosquito larvae targeted for control. A neighborhood pond was surveyed to find a representative species of mosquito as well as other common aquatic insects with which to examine susceptibility to spinosad and non-target effects. The mosquito species chosen was Culex quinquefasciatus and the most common non-target taxa were immature stages of a mayfly (Caenis spp., Ephemeroptera: Caenidae), a damselfly (Ischnura spp., Odonata: Coenagrionidae) and a dragonfly (Pachydiplax longipennis, Odonata: Libellulidae). Bioassays of mosquitoes from a reference susceptible strain (Sebring-S) and field-collections of C. quinquefasciatus were used to determine susceptibility to spinosad. In addition, susceptibility was examined in non-target taxa using spinosad concentrations corresponding to the LC50 of a field-collected mosquitoes (0.031 ppm) and the labeled rate (1.6 ppm) of Natular®, an EC formulation of spinosad. Susceptibility to spinosad did not differ between Sebring-S and field-collected mosquitoes. However, there was a marked difference in susceptibility among non-target taxa. Susceptibility was greatest in Caenis spp., followed by Ischnura spp., then P. longipennis. Results from this study will allow better future management strategies for the use of spinosad as a mosquito larvicidal agent.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-11142012-132731 |
| Date | 21 November 2012 |
| Creators | Jones, Owen McBride |
| Contributors | Carlton, Christopher, Henderson, Gregg, Ottea, James |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-11142012-132731/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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