Modelling Biological Control of Stable Flies by Means of Parasitoids BEKF No. 169 February 2017 Publisher: The Danish Environmental Protection Agency Authors: Henrik Skovgård (Department of Agroecology, University of Aarhus) Gösta-Nachman (Department of Biology, University of Copenhagen) Photos: Henrik Skovgård ISBN: 978-87-93529-69-4 The Danish Environmental Protection Agency publishes reports and papers about research and development projects within the environmental sector, financed by the Agency. The contents of this publication do not necessarily represent the official views of the Danish Environmental Protection Agency. By publishing this report, the Danish Environmental Protection Agency expresses that the content represents an important contribution to the related discourse on Danish environmental policy. Sources must be acknowledged. 2 Environmental Protection Agency / Emne / Titel på publikation Contents Forord ........................................................................................................................... 8 Foreword ....................................................................................................................... 9 Dansk resumé .............................................................................................................. 10 Konklusioner og perspektivering .................................................................................13 Summary ...................................................................................................................... 15 Conclusions and perspectives ..................................................................................... 18 1. Introduction ......................................................................................................... 20 1.1. Background .......................................................................................................................... 20 1.2. Project goals .......................................................................................................................... 21 1.3. Structure of the report ......................................................................................................... 22 2. The stable system ................................................................................................. 23 2.1 Stomoxys calcitrans ............................................................................................................ 23 2.1.1. Taxonomy .............................................................................................................. 23 2.1.2. Life-cycle and development .................................................................................. 23 2.1.3. Ecology .................................................................................................................. 24 2.1.4. Sampling and monitoring populations of stable flies .......................................... 25 2.1.5. Economic importance ........................................................................................... 26 2.1.6. Control methods.................................................................................................... 26 2.2. Spalangia cameroni ............................................................................................................ 28 2.2.1 Taxonomy .............................................................................................................. 28 2.2.2. Life-cycle and development .................................................................................. 29 2.2.3. Ecology .................................................................................................................. 29 2.2.4. Monitoring parasitoid activity .............................................................................. 30 2.2.5. Application and mass production......................................................................... 30 3. The model..............................................................................................................31 3.1. Introduction .......................................................................................................................... 31 3.2. The stable environment ........................................................................................................ 31 3.3. Population structures ........................................................................................................... 31 3.4. Temperature effects on population processes ..................................................................... 31 3.5. Factors affecting survival ..................................................................................................... 32 3.6. Factors affecting fecundity .................................................................................................. 33 Modelling Biological Control of Stable Flies by Means of Parasitoids 3 3.7. Effect of host density on parasitism .................................................................................... 33 3.8. Effect of parasitoid density on parasitism .......................................................................... 33 3.9. Effect of stable fly density on intraspecific competition .................................................... 33 3.10. Manure temperatures .......................................................................................................... 33 3.11. Effect of pesticide application on survival .......................................................................... 34 3.12. Effect of manure removal .................................................................................................... 34 3.13. Spatial effects and dispersal ................................................................................................ 34 3.14. Estimation of parameters .................................................................................................... 34 3.15. The computer program .........................................................................................................35 3.16. Initializing the age distributions ..........................................................................................35 4. Calibration and validation ................................................................................... 36 4.1. Introduction ......................................................................................................................... 36 4.2. The modelled farm system .................................................................................................. 36 4.3. Calibration of manure temperatures................................................................................... 36 4.4. Calibration of the larval competition coefficient .................................................................37 5. Analyses of the system ......................................................................................... 39 5.1. Purposes and general procedure ......................................................................................... 39 5.2. Dynamics of stable flies without parasitoids ...................................................................... 39 5.3 Dynamics of stable flies and parasitoids ............................................................................. 40 6. Sensitivity analysis .............................................................................................. 42 6.1. Purpose and procedure ........................................................................................................ 42 6.2. 42 Results ........................................................................................................................................... 43 7. Control strategies ................................................................................................ 45 7.1. Purposes and general procedure ........................................................................................... 45 7.2. Biological control by means of parasitoids ......................................................................... 45 7.2.1. Release strategies ................................................................................................. 45 7.2.2. Inoculative releases ...............................................................................................47 7.2.3. 47 Preplanned inundative releases .......................................................................................... 48 7.2.4. Adaptive inundative releases ................................................................................ 51 7.3. Chemical control .................................................................................................................. 52 7.3.1. Application strategies........................................................................................... 52 7.3.2. Pre-planned application strategies .......................................................................53 7.3.3. Adaptive application strategies............................................................................ 54 7.4. Physical control by manure removal ................................................................................... 58 7.5. Integrated control ................................................................................................................ 59 4 Modelling Biological Control of Stable Flies by Means of Parasitoids 8. Discussion ...........................................................................................................