Master’s Thesis 2020 60 ECTS Faculty of Environmental Sciences and Natural Resource Management Tortricid pests (Lepidoptera: Tortricidae) in apple orchards of South-Eastern Norway surveyed by pheromone-baited traps Branislav Endel Ecology Acknowledgments I would like to thank my supervisors, Nina Trandem, Gunnhild Jaastad, and Bjørn Arild Hatteland from Norwegian Institute of Bioeconomy Research, who have offered me their advice and guidance through each stage of the process. I would also like to thank to Jop Westplate and Gaute Myren from the Norwegian Agricultural Advisory Service for their generous help and practical advices in the field. My thanks go to Leif Aarvik from Natural History Museum, the University of Oslo for providing me additional information. I am grateful to Peter Horváth, a postgraduate of my previous university, and other former and current classmates for helping me with solving various problems concerning studying in Norway. I am also obligated to Conrad Riepl for his detailed proofreading of the final version of the thesis. Norwegian University of Life Sciences, Ås May 2020 Branislav Endel i Abstract The trend of minimizing pesticide usage in agriculture leads scientists to think about alternatives of how pest numbers can be reduced. The tortricid moths (Lepidoptera: Tortricidae) is a group of insects responsible for great damage in fruit orchards. Efficient models for predicting damage by these moths have so far mainly been developed for the most serious world-wide apple pest, the codling moth Cydia pomonella. Such forecasting models are not well-established for other tortricids and recent data on their status in Norwegian conditions are scare. The overall aim of this study was to provide such data on the flight activity of tortricids attacking apple trees, and thus contribute to the improvement of pest management in Norwegian orchards. The monitoring was undertaken in the Viken and Telemark regions, both in South- Eastern Norway, during 2018 and 2019. In each region, three orchards were selected. Six target species were surveyed by using pheromone-baited traps and some additional collecting of their immature stages. The presence of four out of the six target tortricids, C. pomonella, Pammene rhediella, Archips podana and Hedya nubiferana, was confirmed in high numbers. One species, Adoxophyes orana, was very rare in all the orchards and another, Pandemis heparana appeared to be rare, probably due to a poorly functioning pheromone attractant. Differences in flight activity between the two years, one abnormally hot (2018) and the other slightly warmer than an average year (2019) were prominent. It was found that minimum temperature better explained the flight activity of 2 of the target species (spring and early summer ones), but in the case of A. podana (late summer species) the maximum temperature seemed to be a more important limiting factor. The majority (67%) of lepidopteran individuals caught by the pheromone traps belonged to the six target species. Regarding the remainder, 15% represented other pests and 18% were of species not considered as pests. Two pheromone lures, the ones employed for C. pomonella and P. rhediella, appeared to be reciprocal (attracting both target species). The lure for H.nubiferna trapped a greater amount of the non-target pest tortricid Grapholita funebrana than of the target. The lure for P. heparana surprisingly appeared to be more specific for the non-target pest tortricid Ptycholoma lecheana. Such a high proportion of non-target species caught in the target traps suggested that this issue needs to be taken into account. Their identification may be complicated for persons with little entomological experience. ii Table of Contents Acknowledgments ..................................................................................................................... i Abstract .................................................................................................................................... ii Abbreviations ........................................................................................................................... v 1 Introduction ............................................................................................................................ 1 2 Material and methods ............................................................................................................. 4 2.1 Study area ......................................................................................................................... 4 2.2 The six target species ....................................................................................................... 5 2.3 Sampling in the orchards .................................................................................................. 7 2.4 Identification and laboratory work ................................................................................... 8 2.5 Meteorological data .......................................................................................................... 9 2.6 Statistical analysis .......................................................................................................... 10 3 Results .................................................................................................................................. 11 3.1 Abundance and flight period .......................................................................................... 11 3.1.1 General overview of trap catches ............................................................................. 11 3.1.2 Target tortricids ........................................................................................................ 11 3.1.3 Other pest tortricids .................................................................................................. 14 3.1.4 Other lepidopteran pests ........................................................................................... 15 3.1.5 Catches of moths not considered as pests ................................................................ 17 3.2 Relationship between larval and adult occurrence ......................................................... 18 3.3 Factors affecting catch extent ......................................................................................... 20 3.3.1 Production system and trap placement ..................................................................... 20 3.3.2 Temperature ............................................................................................................. 21 iii 3.4 Specificity of pheromone lures ...................................................................................... 26 4 Discussion ............................................................................................................................ 27 4.1 Flight activity of target tortricids ................................................................................... 27 4.2 Flight activity of other Lepidoptera ............................................................................... 28 4.3 Relationship between larval and adult occurrence ......................................................... 30 4.4 Factors affecting adults’ abundance ............................................................................... 32 4.4.1 Production system .................................................................................................... 32 4.4.2 Trap placement ......................................................................................................... 33 4.4.3 Temperature ............................................................................................................. 34 4.5 Specificity of pheromone lures ...................................................................................... 36 4.5.1 Identification of species recorded by pheromone traps ............................................ 37 5 Conclusions .......................................................................................................................... 38 Literature ................................................................................................................................. 39 APPENDIX 1 ............................................................................................................................ I APPENDIX 2 .......................................................................................................................... III APPENDIX 3 ........................................................................................................................... V APPENDIX 4 .......................................................................................................................... VI iv Abbreviations IPM – Integrated Pest Management NHM UiO – Natural History Museum, University of Oslo NLR – Norwegian Agricultural Advisory Service (Norsk Landbruksrådgiving) SID – Simpson's index of diversity LMT – Agricultural Meteorological Service (Landbruks Meteorologisk Tjeneste) Acronyms of the lures: CYPO – the codling moth Cydia pomonella (Linnaeus, 1758) PARH – the fruitlet mining tortrix Pammene rhediella (Clerck, 1759) HENU – the marbled orchard tortrix Hedya nubiferana (Haworth, 1811), syn. H. dimidioalba ARPO – the large fruit-tree tortrix Archips podana (Scopoli, 1763) ADOR – the summer fruit tortrix Adoxophyes orana (Fischer V. Röslerstamm, 1834) PAHE – the dark fruit-tree tortrix Pandemis heparana (Denis & Schiffermüller, 1775)