Title page for ETD etd-04202012-150457


Type of Document Master's Thesis
Author Brown, Sebe Anthony
Author's Email Address sbrown@agcenter.lsu.edu
URN etd-04202012-150457
Title Evaluating the Efficacy of Methoxyfenozide on Louisiana, Texas and the Mid-Southern Soybean Looper Populations
Degree Master of Science (M.S.)
Department Entomology
Advisory Committee
Advisor Name Title
Davis, Jeffrey Committee Chair
Leonard, Billy Rogers Committee Member
Ottea, James Committee Member
Reagan, Thomas Eugene Committee Member
Way, Michael Orrin Committee Member
Keywords
  • Lepidoptera
  • Noctuidae
  • Bioassay
Date of Defense 2012-04-04
Availability unrestricted
Abstract
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 g/ml) of methoxyfenozide in diet incorporation bioassays. All field colonies were compared to a reference strain LC50 of 0.007 g/ml for 2009 and 0.008 g/ml for 2010. Louisiana populations exhibited LC50s of 0.079 g/ml and 0.122 g/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 g/ml in 2009 and 0.011 g/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).
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