Promoters: Prof. dr. ir. Patrick De Clercq Department of Crop Protection, Laboratory of Agrozoology, Faculty of Bioscience Engineering, Ghent University Prof. dr. ir. Luc Tirry Department of Crop Protection, Laboratory of Agrozoology, Faculty of Bioscience Engineering, Ghent University Dr. Bruno Gobin, PCS- Ornamental Plant Research Dean: Prof. dr. ir. Marc Van Meirvenne Rector: Prof. dr. Anne De Paepe Effects of temperature regime and food supplementation on the performance of phytoseiid mites as biological control agents by Ir. Dominiek Vangansbeke Thesis submitted in the fulfillment of the requirements for the Degree of Doctor (PhD) in Applied Biological Sciences Dutch translation: Effecten van temperatuurregime en voedingssupplementen op de prestaties van Phytoseiidae roofmijten als biologische bestrijders Please refer to this work as follows: Vangansbeke, D. (2015) Effects of temperature regime and food supplementation on the performance of phytoseiid mites as biological control agents. Ghent University, Ghent, Belgium Front and backcover photographs: Dominiek Vangansbeke ISBN-number: 978-90-5989-847-9 This study was funded by grant number 090931 from the Institute for Promotion of Innovation by Science and Technology in Flanders (IWT). The research was conducted at the Laboratory of Agrozoology, Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium and partly at PCS-Ornamental Plant Research, Schaessestraat 18, 9070 Destelbergen, Belgium The author and promoters give permission to use this study for consultation and to copy parts of it for personal use only. Every other use is subject to the copyright laws. Permission to reproduce any material should be obtained from the author. Table of content List of abbreviations ..........................................................................................................................i Scope and thesis outline .................................................................................................................. iii Chapter 1: Phytoseiidae as biological control agents ....................................................................... 1 1.1 The diversity of the Acari .......................................................................................................... 2 1.2 Adoption of phytoseiid predatory mites as biological control agents in covered crops ................ 2 1.3 Taxonomy ................................................................................................................................ 3 1.4 Origin and distribution .............................................................................................................. 4 1.5 Morphological characteristics .................................................................................................... 4 1.6 Bionomics ................................................................................................................................. 8 1.6.1 Development ...................................................................................................................... 8 1.6.1 Egg stage .................................................................................................................................... 8 1.6.2 Larval and nymphal stages ........................................................................................................ 10 1.6.2 Reproduction .................................................................................................................... 15 1.6.3 Diapause induction ........................................................................................................... 17 1.6.4 Feeding habits .................................................................................................................. 17 1.6.4.1 Prey food ............................................................................................................................... 20 1.6.4.1.1 Mite prey ............................................................................................................... 20 1.6.4.1.1.1 Tetranychidae ........................................................................................ 20 1.6.4.1.1.2 Eriophyoidea ......................................................................................... 22 1.6.4.1.1.3 Tarsonemidae ........................................................................................ 23 1.6.4.1.1.4 Tetranychidae ........................................................................................ 23 1.6.4.1.2 Thripidae ............................................................................................................... 23 1.6.4.1.3 Aleyrodidae ........................................................................................................... 25 1.6.4.1.4 Cannibalism........................................................................................................... 26 1.6.4.1.5 Intraguild predation................................................................................................ 27 1.6.4.2 Alternative food ..................................................................................................................... 28 1.6.4.2.1 Plant tissue ............................................................................................................ 28 1.6.4.2.2 Pollen .................................................................................................................... 28 1.6.4.2.3 Extrafloral nectar ................................................................................................... 30 1.6.4.2.4 Honeydew ............................................................................................................. 30 1.6.4.3 Factitious prey ....................................................................................................................... 31 1.6.4.4 Artificial diets ........................................................................................................................ 33 1.6.4.5 Phytoseiidae as biological control agents ................................................................................ 34 1.7 Release techniques for predatory mites .................................................................................... 36 1.8 Conservation of predatory mites .............................................................................................. 38 1.8.1 Pest-in-first .................................................................................................................................... 39 1.8.2 Banker plant system ....................................................................................................................... 39 1.8.3 Importance of host plant ................................................................................................................. 41 1.8.4 Herbivore-induced plant volatiles and semiochemicals ................................................................... 42 1.8.5 Food supplements ............................................................................................................. 42 1.9 Adaptation to the greenhouse climate ...................................................................................... 47 Chapter 2: Diurnal temperature variations affect development and population growth of Tetranychus urticae and it phytoseiid predators Phytoseiulus persimilis and Neoseiulus californicus ..................................................................................................................................... 49 2.1 Introduction ............................................................................................................................. 50 2.2 Material and methods .............................................................................................................. 52 2.2.1 Mite rearing ................................................................................................................................... 52 2.2.1.1 Spider mites ........................................................................................................................... 52 2.2.1.2 Predatory mites ...................................................................................................................... 53 2.2.2 Experiment 1: Developmental rates ................................................................................................ 53 2.2.2.1 Experimental set-up ............................................................................................................... 53 2.2.2.2 Statistical analysis .................................................................................................................. 54 2.2.2.3 Modelling .............................................................................................................................. 55 2.2.2.3.1 Linear regression ........................................................................................................ 55 2.2.2.3.2 Nonlinear regression ................................................................................................... 56 2.2.2.4 Model evaluation .................................................................................................................. 57 2.2.2.5 Potential impact on biological control .................................................................................... 58 2.2.3 Experiment 2: Population