Department of Agronomy, Food, Natural Resources, Animals and the Environment __________________________________________________________________________ DOCTORAL SCHOOL OF CROP SCIENCES CURRICULUM: CROP PROTECTION CYCLE: XXV THE IMPACT OF PESTICIDES ON APPLE MITE COMMUNITIES Director of the school: Ch.mo Prof. Angelo Ramina Coordinator: Ch.mo Prof Francesco Favaron Supervisor: Ch.mo Prof. Carlo Duso Ph.D. Candidate: Shakeel Ahmad Declaration I hereby declare that this submission is my own work and that, to the best of my knowledge and belief, it contains no material previously published or written by another person nor material which to a substantial extent has been accepted for the award of any other degree or diploma of the university or other institute of higher learning, except where due acknowledgment has been made in the text. December, 31st 2012 Shakeel Ahmad A copy of the thesis will be available at http://paduaresearch.cab.unipd.it/ Dichiarazione Con la presente affermo che questa tesi è frutto del mio lavoro e che, per quanto io ne sia a conoscenza, non contiene materiale precedentemente pubblicato o scritto da un'altra persona né materiale che è stato utilizzato per l’ottenimento di qualunque altro titolo o diploma dell'università o altro istituto di apprendimento, a eccezione del caso in cui ciò venga riconosciuto nel testo. 31 Decembre, 2012 Shakeel Ahmad Una copia della tesi sarà disponibile presso http://paduaresearch.cab.unipd.it/ 2 Table of contents Table of contents........................................................................................................................3 Riassunto....................................................................................................................................6 Summary.....................................................................................................................................9 Chapter I – Introduction........................................................................................................12 Mites..........................................................................................................................................13 Role of phytoseiid mites .................................................................................................. 14 Phytoseiid mites in orchards and vineyards in northern Italy ......................................... 15 Factors affecting phytoseiid mite performance ............................................................... 16 Effects of pesticides on phytoseiids................................................................................. 18 References ................................................................................................................................ 21 Chapter II – Augmentative releases of the predatory mite Kampimodromus aberrans in organic and conventional apple orchards.............................................................................30 Abstract .................................................................................................................................... 31 Introduction ............................................................................................................................. 31 Materials and Methods ............................................................................................................ 33 Experimental orchards ..................................................................................................... 33 Experimental design ........................................................................................................ 33 Statistical analysis............................................................................................................ 34 Results ...................................................................................................................................... 35 Mite population dynamics in orchards (2010 releases) ................................................... 35 Mite population dynamics in orchards (2011 releases) ................................................... 36 Mite population dynamics in Florina and Golden Delicious orchards (Spresiano, 2010 trials) ..................................................................................................................................... 37 Mite population dynamics in Florina and Golden Delicious orchards (Spresiano, 2011 trials) ..................................................................................................................................... 38 Discussion ................................................................................................................................ 40 References ................................................................................................................................ 43 Figures and tables....................................................................................................................49 3 Chapter III - Predation on heterospecific larvae by adult females of Kampimodromus aberrans, Amblyseius andersoni, Typhlodromus pyri and Phytoseius finitimus (Acari: Phytoseiidae) ...........................................................................................................................56 Abstract .................................................................................................................................... 57 Introduction ............................................................................................................................. 57 Materials and Methods ............................................................................................................ 60 Stock cultures .................................................................................................................. 60 Experimental procedures ................................................................................................. 60 Data analysis .................................................................................................................... 61 Results ...................................................................................................................................... 62 Predatory mite performance on heterospecific larvae ..................................................... 62 Comparative performance of predatory mites on the same prey ..................................... 63 Survival and age-specific oviposition curves on pollen and prey ................................... 65 Discussion ................................................................................................................................ 67 References ................................................................................................................................ 72 Figures and tables....................................................................................................................80 Chapter IV – The impact of insecticides applied in apple orchards on the predatory mite Kampimodromus aberrans (Acari: Phytoseiidae) .................................................................89 Abstract .................................................................................................................................... 90 Introduction ............................................................................................................................. 90 Materials and Methods ............................................................................................................ 92 Field studies ..................................................................................................................... 92 Laboratory studies ........................................................................................................... 94 Results ...................................................................................................................................... 94 Field studies ..................................................................................................................... 94 Laboratory studies ........................................................................................................... 96 Discussion ................................................................................................................................ 97 References .............................................................................................................................. 101 Figures and tables..................................................................................................................109 Chapter V – Does pollen availability mitigate the impact of pesticides on predatory mites? .....................................................................................................................................118 Abstract .................................................................................................................................. 119 4 Introduction ........................................................................................................................... 120 Materials and methods .......................................................................................................... 122 Study system .................................................................................................................. 122 Laboratory experiments ................................................................................................