The soybean looper, Chrysodeixis includens (Walker), is a defoliating insect pest of soybean in the Mid-South and Texas. In 2008, Louisiana producers reported unsatisfactory control of soybean loopers in soybean with methoxyfenozide. In 2009 and 2010, field collections from Louisiana, Missouri, Mississippi and Texas were exposed to discriminating concentrations (0.020 to 5.000 ai ìg/ml) of methoxyfenozide in diet incorporation bioassays. All field colonies were compared to a reference strain LC50 of 0.007 ìg/ml for 2009 and 0.008 ìg/ml for 2010. Louisiana populations exhibited LC50s of 0.079 ìg/ml and 0.122 ìg/ml for 2009 and 2010, respectively, which were the highest values among all field collections during three years. The Missouri collections demonstrated the lowest LC50s with 0.025 ìg/ml in 2009 and 0.011 ìg/ml in 2010. In general, results of these discriminating concentration tests indicated that all field collections showed elevated LC50s compared to the reference colony. Additional field experiments were conducted to evaluate the efficacy of foliar insecticides against Louisiana soybean loopers. Significant differences among treatments for defoliation area were determined between lepidopteran specific and broad spectrum insecticides. For the 2009-10 experiment chlorantraniliprole had the lowest defoliation 3,7,14,21 and 28 days after treatment (DAT) (0.20, 0.20, 0.50, 0.57, 0.97 cm2) while lambda-cyhalothrin had the highest (1.12, 2.38, 2.06, 2.79, 2.25 cm2). In 2011, defoliation and days to 100% mortality were evaluated at two locations for R3 and R5 development stages. Chlorantraniliprole provided the lowest days to mortality (2.3) at R3 and (1.0) at R5 while oxadiazine resulted in the highest (5.7 and 6.0).
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-04202012-150457 |
| Date | 25 April 2012 |
| Creators | Brown, Sebe Anthony |
| Contributors | Davis, Jeffrey, Leonard, Billy Rogers, Way, Michael Orrin, Reagan, Thomas Eugene, 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-04202012-150457/ |
| 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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