|LOPEZ, JUAN DE DIOS - Retired ARS Employee|
|Latheef, Mohamed - Ab|
|REE, BILL - Texas A&M Agrilife|
Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/29/2012
Publication Date: 12/15/2012
Citation: Lopez, J., Latheef, M.A., Ree, B., Hoffmann, W.C. 2012. Toxicity to adult brown stink bug (Hemiptera: Pentatomidae) in a glass-vial bioassay of selected insecticide mixture. Southwestern Entomologist. 37(4):459-466.
Interpretive Summary: The brown stink bug has become the predominant species among the stink bug complex on cotton in Central Texas and effective control of these pests is largely dependent upon and limited to the use of insecticides. Studies were conducted to assess the toxicity of currently available insecticides and to develop baseline mortality data to monitor resistance of the insect to insecticides. Toxicity studies for selected insecticides via glass-vial bioassays showed that commercial formulations were less toxic than technical materials and lack synergism when multiple active compounds were present in the formulations. Baseline mortality data for brown stink bug presented herein are useful for comparison with local populations should suspicion of tolerance to these insecticides develop in Central Texas.
Technical Abstract: The brown stink bug (BSB), Euschistus servus (Say) has become the predominant species among the stink bug complex on cotton in Central Texas. Control options to suppress the insect are largely dependent upon and limited to the use of insecticides. Data are needed to determine the toxicity of currently available insecticides to BSB and to develop baseline mortality data to assess resistance to insecticides in Central Texas. Using a glass vial bioassay, the LC10 and LC50 values for selected commercially formulated insecticides, the technical grade active ingredients and the mixtures of active ingredients were determined for BSB captured in blacklight traps established near farm lands in Caldwell County, Texas. The LC10 and LC50 values, respectively, showed that the mixtures of technical grade insecticides were 37- to 526 and 58- to 384-fold more toxic to BSB compared to their respective commercial formulations. The toxicological response of the technical grade active ingredients relative to the mixtures varied from synergistic to antagonistic. Baseline mortality data for BSB presented herein are useful for comparison with local populations should suspicion of tolerance to these insecticides develop in Central Texas. Data demonstrate lack of potentiation of the mixtures, probably due to absence of additivity or synergism in the composition of active and inert ingredients used in the formulations or decreased composition of each component in the formulated mixtures.