Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2015 Screening of herbicides for selective weed control in African marigold (Tagetes erecta) Katie Jean Demers Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Agricultural Science Commons, Agriculture Commons, Agronomy and Crop Sciences Commons, and the Horticulture Commons Recommended Citation Demers, Katie Jean, "Screening of herbicides for selective weed control in African marigold (Tagetes erecta)" (2015). Graduate Theses and Dissertations. 14321. https://lib.dr.iastate.edu/etd/14321 This Thesis is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Screening of herbicides for selective weed control in African marigold ( Tagetes erecta ) by Katie Jean Demers A thesis submitted to the graduate faculty in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Major: Crop Production and Physiology (Weed Science) Program of Study Committee: Robert Hartzler, Major Professor Micheal Owen Nick Christians Iowa State University Ames, Iowa 2015 Copyright © Katie Jean Demers, 2015. All rights reserved. ii TABLE OF CONTENTS LIST OF FIGURES .......................................................................................................... iii LIST OF TABLES ............................................................................................................ iv ABSTRACT ..................................................................................................................... vii CHAPTER I: GENERAL INTRODUCTION ...................................................................... 1 Introduction ................................................................................................................ 1 Thesis Organization ................................................................................................... 4 CHAPTER II: SCREENING OF HERBICIDES FOR SELECTIVE WEED CONTROL IN AFRICAN MARGIOLD ( TAGETES ERECTA ) ......................................... 5 Abstract ..................................................................................................................... 5 Introduction ................................................................................................................ 6 Materials and Methods ............................................................................................... 8 Results and Discussion ............................................................................................ 12 Summary and Conclusions ...................................................................................... 21 References .............................................................................................................. 22 CHAPTER III: AFRICAN MARIGOLD ( TAGETES ERECTA ) RESPONSE TO TOPRAMEZONE ................................................................................ 43 Abstract .................................................................................................................... 43 Introduction .............................................................................................................. 44 Materials and Methods ............................................................................................. 47 Results and Discussion ............................................................................................ 50 Summary and Conclusions ...................................................................................... 55 References .............................................................................................................. 56 CHAPTER IV: GENERAL CONCLUSIONS .................................................................. 63 APPENDIX: ADDITIONAL TABLES .............................................................................. 65 ACKNOWLEDGEMENTS ............................................................................................. 67 iii LIST OF FIGURES Figure 1 Phytotoxicity response of African marigold to seven rates of topramezone fifteen days after application. Injury rating scale 1-9, 1=normal growth 9=plant death . 59 iv LIST OF TABLES Table 1 Preemergence herbicides and 1X rate used in greenhouse experiments ................................................................................................ 25 Table 2 Postemergence herbicides, 1X rate, and additives used in greenhouse experiments ............................................................................ 25 Table 3 Emergence and phytotoxicity response of greenhouse grown African marigold to oryzalin applied preemergence .................................... 26 Table 4 Emergence and phytotoxicity response of greenhouse grown African marigold to pendimethalin applied preemergence .......................... 26 Table 5 Emergence and phytotoxicity response of greenhouse grown African marigold to trifluralin applied preemergence ................................... 27 Table 6 Emergence and phytotoxicity response of greenhouse grown African marigold to EPTC applied preemergence....................................... 27 Table 7 Emergence and phytotoxicity response of greenhouse grown African marigold to oxyfluorfen applied preemergence ............................... 28 Table 8 Emergence and phytotoxicity response of greenhouse grown African marigold to acetochlor applied preemergence ................................ 28 Table 9 Emergence and phytotoxicity response of greenhouse grown African marigold to encapsulated acetochlor applied preemergence ......... 29 Table 10 Emergence and phytotoxicity response of greenhouse grown African marigold to napropamide applied preemergence ........................... 29 Table 11 Emergence and phytotoxicity response of greenhouse grown African marigold to pyroxasulfone applied preemergence .......................... 30 Table 12 Emergence and phytotoxicity response of greenhouse grown African marigold to S-metolachlor applied preemergence .......................... 30 Table 13 Emergence and phytotoxicity response of greenhouse grown African marigold to bensulide applied preemergence ................................. 31 Table 14 Emergence and phytotoxicity response of field grown African marigold to preplant incorporated herbicide applications ............................ 32 v Table 15 Emergence and phytotoxicity response of field grown African marigold to preemergence herbicide applications ..................... 33 Table 16 Emergence and phytotoxicity response of field grown African marigold to preplant incorporated and preemergence herbicide applications ............................................... 34 Table 17 Phytotoxicity response of greenhouse grown African marigold to imazamox applied postemergence .................................................. 35 Table 18 Phytotoxicity response of greenhouse grown African marigold to imazethapyr applied postemergence ................................................ 35 Table 19 Phytotoxicity response of greenhouse grown African marigold to 2,4-DB applied postemergence ....................................................... 36 Table 20 Phytotoxicity response of greenhouse grown African marigold to atrazine applied postemergence ..................................................... 36 Table 21 Phytotoxicity response of greenhouse grown African marigold to bentazon applied postemergence .................................................... 37 Table 22 Phytotoxicity response of greenhouse grown African marigold to acifluorfen applied postemergence .................................................. 37 Table 23 Phytotoxicity response of greenhouse grown African marigold to flumiclorac applied postemergence .................................................. 38 Table 24 Phytotoxicity response of greenhouse grown African marigold to carfentrazone applied postemergence .............................................. 38 Table 25 Phytotoxicity response of greenhouse grown African marigold to fluthiacet-methyl applied postemergence .......................................... 39 Table 26 Phytotoxicity response of greenhouse grown African marigold to fomesafen applied postemergence .................................................. 39 Table 27 Phytotoxicity response of greenhouse grown African marigold to lactofen applied postemergence ..................................................... 40 Table 28 Phytotoxicity response of greenhouse grown African marigold to acetochlor applied postemergence .................................................. 40 vi Table 29 Phytotoxicity response of greenhouse grown African marigold to encapsulated acetochlor applied postemergence ............................... 41 Table 30 Phytotoxicity response of greenhouse grown African marigold to mesotrione applied postemergence ................................................. 41 Table 31 Phytotoxicity response of greenhouse grown African marigold to tembotrione applied postemergence ................................................ 42 Table 32 Phytotoxicity response of greenhouse grown African marigold to topramezone applied postemergence .............................................. 42 Table