Meike Brandes Institut für Pfl anzenschutz in Ackerbau und Grünland Eff ects of diff erent insecticide applications on population development of pollen beetle (Meligethes aeneus (Fabricius)) on oilseed rape (Brassica napus L.) Dissertationen aus dem Julius Kühn-Institut Julius Kühn-Institut Bundesforschungsinstitut für Kulturpfl anzen Kontakt/Contact: Meike Brandes Julius Kühn-Institut Bundesforschungsinstitut für Kulturpflanzen Institut für Pflanzenschutz in Ackerbau und Grünland Messeweg 11-12 38104 Braunschweig Die Schriftenreihe ,,Dissertationen aus dem Julius Kühn-lnstitut" veröffentlicht Doktorarbeiten, die in enger Zusammenarbeit mit Universitäten an lnstituten des Julius Kühn-lnstituts entstanden sind. The publication series „Dissertationen aus dem Julius Kühn-lnstitut" publishes doctoral dissertations originating from research doctorates and completed at the Julius Kühn-Institut (JKI) either in close collaboration with universities or as an outstanding independent work in the JKI research fields. Der Vertrieb dieser Monographien erfolgt über den Buchhandel (Nachweis im Verzeichnis lieferbarer Bücher - VLB) und OPEN ACCESS im lnternetangebot www.julius-kuehn.de Bereich Veröffentlichungen. The monographs are distributed through the book trade (listed in German Books in Print - VLB) and OPEN ACCESS through the JKI website www.julius-kuehn.de (see Publications). Wir unterstützen den offenen Zugang zu wissenschaftlichem Wissen. Die Dissertationen aus dem Julius Kühn-lnstitut erscheinen daher OPEN ACCESS. Alle Ausgaben stehen kostenfrei im lnternet zur Verfügung: http://www.julius-kuehn.de Bereich Veröffentlichungen. We advocate open access to scientific knowledge. 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ISBN 978-3-95547-044-9 DOI 10.5073/dissjki.2017.003 Herausgeber l Editor Julius Kühn-lnstitut, Bundesforschungsinstitut für Kulturpflanzen, Quedlinburg, Deutschland Julius Kühn-lnstitut, Federal Research Centre for Cultivated Plants, Quedlinburg, Germany Dieses Werk ist lizenziert unter einer Creative Commons – Namensnennung – Weitergabe unter gleichen Bedingungen – 4.0 Lizenz. This work is licensed under a Creative Commons – Attribution – ShareAlike – 4.0 license. Effects of different insecticide applications on population development of pollen beetle (Meligethes aeneus (Fabricius)) on oilseed rape (Brassica napus L.) Dissertation zur Erlangung des Doktorgrades der Fakultät für Agrarwissenschaften der Georg-August-Universität Göttingen vorgelegt von Meike Brandes geboren in Braunschweig Göttingen, November 2016 D 7 1. Referent: Prof. Dr. Stefan Vidal 2. Korreferent: Prof. Dr. Andreas von Tiedemann Tag der mündlichen Prüfung: 11. November 2016 I Table of contents Summary .............................................................................................................................. 1 Zusammenfassung .............................................................................................................. 3 Chapter I General introduction ........................................................................................................... 5 Oilseed rape and its pests.................................................................................................. 5 Pyrethroid resistance ......................................................................................................... 5 Biology of the pollen beetle ................................................................................................ 6 Factors influencing population development of the pollen beetle........................................ 7 Objectives of the study ......................................................................................................10 References .......................................................................................................................12 Chapter II Effects of the neonicotinoid Biscaya and the pyrethroids Mavrik and Karate Zeon on overwintered pollen beetles (Meligethes aeneus (Fabricius)) and their offspring in oilseed rape ........................................................................................................................18 Abstract ............................................................................................................................18 Introduction .......................................................................................................................18 Materials and Methods ......................................................................................................20 Results..............................................................................................................................24 Discussion ........................................................................................................................31 References .......................................................................................................................35 Chapter III Impact of the insecticides Biscaya, Mavrik and Karate Zeon on infestation of buds with eggs and larvae of pollen beetle (Meligethes aeneus (Fabricius)) ..........................41 Abstract ............................................................................................................................41 Introduction .......................................................................................................................42 Materials and Methods ......................................................................................................43 Results..............................................................................................................................47 Discussion ........................................................................................................................56 References .......................................................................................................................60 II Chapter IV Effects of neonicotinoid and pyrethroid insecticide applications on the parasitism rates of pollen beetle larvae (Meligethes aeneus (Fabricius)) by tersilochine parasitoids ..........................................................................................................................64 Abstract ............................................................................................................................64 Introduction .......................................................................................................................64 Materials and Methods ......................................................................................................66 Results..............................................................................................................................68 Discussion ........................................................................................................................72 References .......................................................................................................................78 Chapter V General discussion ............................................................................................................81 Effects on overwintered pollen beetles ..............................................................................81 Effects on bud infestation with eggs and larvae ................................................................82 Effects on larval stages and new generation pollen beetles ..............................................83 Effects on parasitism rates of pollen beetle larvae ............................................................85 Alternative control strategies .............................................................................................86 Conclusion ........................................................................................................................87 References .......................................................................................................................89 Erklärungen ........................................................................................................................95 Danksagung ........................................................................................................................96 Curriculum vitae .................................................................................................................97 1 Summary The pollen beetle, Meligethes aeneus (Fabricius) (syn. Brassicogethes aeneus (Fabricius)) is a major pest in the production of oilseed rape, Brassica napus L., in Europe. At high levels of crop infestation, adult beetles can cause severe economic damage by destroying the buds. Chemical control of this pest is biased due to the widely distributed pyrethroid resistance and a decreasing availability of insecticides with different modes of action. Effective