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Biology and Management of the Dutch Elm Disease Vector, Hylurgopinus Rufipes Eichhoff (Coleoptera: Curculionidae) in Manitoba By

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Biology and Management of the Dutch Elm Disease Vector, Hylurgopinus Rufipes Eichhoff (Coleoptera: Curculionidae) in Manitoba By Biology and Management of the Dutch Elm Disease Vector, Hylurgopinus rufipes Eichhoff (Coleoptera: Curculionidae) in Manitoba by Sunday Oghiakhe A thesis submitted to the Faculty of Graduate Studies of The University of Manitoba in partial fulfilment of the requirements of the degree of Doctor of Philosophy Department of Entomology University of Manitoba Winnipeg Copyright © 2014 Sunday Oghiakhe Abstract Hylurgopinus rufipes, the native elm bark beetle (NEBB), is the major vector of Dutch elm disease (DED) in Manitoba. Dissections of American elms (Ulmus americana), in the same year as DED symptoms appeared in them, showed that NEBB constructed brood galleries in which a generation completed development, and adult NEBB carrying DED spores would probably leave the newly-symptomatic trees. Rapid removal of freshly diseased trees, completed by mid-August, will prevent spore-bearing NEBB emergence, and is recommended. The relationship between presence of NEBB in stained branch sections and the total number of NEEB per tree could be the basis for methods to prioritize trees for rapid removal. Numbers and densities of overwintering NEBB in elm trees decreased with increasing height, with >70% of the population overwintering above ground doing so in the basal 15 cm. Substantial numbers of NEBB overwinter below the soil surface, and could be unaffected by basal spraying. Mark-recapture studies showed that frequency of spore bearing by overwintering beetles averaged 45% for the wild population and 2% for marked NEBB released from disease-free logs. Most NEBB overwintered close to their emergence site, but some traveled ≥4.8 km before wintering. Studies comparing efficacy of insecticides showed that chlorpyrifos gave 100% control of overwintering NEBB for two years as did bifenthrin: however, permethrin and carbaryl provided transient efficacy. NEBB showed a gradual increase in development rate with increasing constant temperature. Lipid content of overwintering NEBB was higher in late fall than in mid-winter, which might show that depletion of fat reserves could jeopardize survival, but could be a result of conversion to cryoprotectants. Acknowledgements I would like to express my gratitude to my major advisor Dr. N. J. Holliday, for his support and guidance, for asking insightful questions, and offering invaluable advice. My sincere thanks go to my committee members, Dr. A. Farenhorst, Dr. G. Hausner, Dr. R. L. McIntosh and Dr. R. Westwood, for their helpful comments and suggestions on my research project. Also, I thank Dr. N. J. Holliday and my committee members for their empathy and tremendous assistance especially since I suffered a stroke a few years ago. This research project would not have been completed without your encouragement and understanding. Assistance and facilitation were provided by J. Leferink and the staff of Manitoba Conservation Forestry Branch, D. Domke and staff of the City of Winnipeg Urban Forestry Branch and S. Mutchmor and staff of the Coalition to Save the Elms (Trees Winnipeg). I thank G. Richardson and H. Epp for allowing use of elm trees on their property. Technical assistance was provided by L. Babey, D. Holder, B. Rogala, J. Veilleux, P. Turko, L. Christianson and S. Surowiec. I have also received a great deal of care and assistance from T. Galloway, B. Sharanowski, L. Holliday, P. Fields, W. Akinremi, Phillip and Irene Pines, K. Graham, T. Nagalingam, J. Du, R. Bahreini and S. Raafat, and Pastor Samuel and Helen Paul. The financial support of the Sustainable Development Initiatives Fund, Manitoba, Manitoba Conservation, City of Winnipeg, Saskatchewan Ministry of Environment, the Natural Sciences and Engineering Research Council of Canada, University of Manitoba, Trees Winnipeg and seventeen Manitoba Municipalities, is gratefully acknowledged. I thank Gardex Chemical Ltd and FMC Corporation for providing insecticides. iii Lastly, I thank my family members for their support, especially my wonderful parents- my late father, Mr. D. Oghiakhe and my mother, Mrs. J. Oghiakhe for their encouragement, love and support. iv Table of Contents Abstract ........................................................................................................................... ii Acknowledgements ........................................................................................................ iii List of Tables ................................................................................................................. ix List of Figures .............................................................................................................. xiii List of copyright clearances for items in the thesis...................................................... xvi Chapter 1: Introduction ....................................................................................................... 1 Chapter 2: Literature review ............................................................................................. 11 Introduction and review objectives ............................................................................... 11 Biology of the organisms involved in Dutch elm disease............................................. 13 Biology of American elm, Ulmus americana L. (Ulmaceae) ................................... 13 Biology of Hylurgopinus rufipes (Eichhoff)............................................................. 17 Biology of Ophiostoma novo-ulmi............................................................................ 24 Interactions involving Hylurgopinus rufipes ............................................................ 32 Dutch elm disease in Manitoba ..................................................................................... 36 Economics of Dutch elm disease in Manitoba .......................................................... 38 Control of Dutch elm disease, with emphasis on the prairie region ............................. 39 Dutch elm disease surveys ........................................................................................ 40 Sanitation .................................................................................................................. 41 Basal insecticide application ..................................................................................... 43 v Biological control...................................................................................................... 44 Root graft severance ................................................................................................. 46 Preventive pruning .................................................................................................... 46 Regulatory control .................................................................................................... 47 Fungicide injection.................................................................................................... 47 Trap trees .................................................................................................................. 48 Integrated disease control ......................................................................................... 49 Potential improvements to disease management in Manitoba ...................................... 51 Chapter 3: Brood development of Hylurgopinus rufipes Eichhoff (Coleoptera: Curculionidae) in American elm trees newly diagnosed with Dutch elm disease in Manitoba ........................................................................................................................... 53 Introduction ................................................................................................................... 54 Material and Methods ................................................................................................... 57 Detection of Ophiostoma novo-ulmi in samples ....................................................... 58 Statistical analysis ..................................................................................................... 61 Results ........................................................................................................................... 61 Discussion ..................................................................................................................... 66 Implications for management of Dutch elm disease ................................................. 74 Chapter 4: Overwintering of the native elm bark beetle, Hylurgopinus rufipes Eichhoff (Coleoptera: Curculionidae), in American elm trees, Ulmus americana L. (Ulmaceae) in Manitoba ........................................................................................................................... 91 vi Introduction ................................................................................................................... 92 Materials and Methods .................................................................................................. 94 Study sites ................................................................................................................. 94 Vertical distribution of over-wintering Hylurgopinus rufipes .................................. 95 Detection of Ophiostoma novo-ulmi spores .............................................................. 97 Mark-recapture studies on H. rufipes........................................................................ 98 Statistical analysis ....................................................................................................
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