Varroa mite management among small-scale beekeepers

139 Pages·2016·2.48 MB·English

Varroa mite management among small-scale beekeepers:
Characterizing factors that affect IPM adoption, and exploring drone brood
removal as an IPM tool

THESIS

Presented in Partial Fulfillment of the Requirements for the Degree Master of Science
In the Graduate School of The Ohio State University

By

Hannah R. Whitehead

Graduate Program in Environmental Science

The Ohio State University

2017

Master’s Examination Committee:

Dr. Casey Hoy, Advisor

Dr. Reed Johnson

Dr. Anna Willow
Copyrighted by
Hannah R. Whitehead
2017
ABSTRACT

Varroa mites (Varroa destructor) are the most damaging pest in modern
beekeeping, and have been linked with elevated levels of colony loss. Experts
increasingly recommend an integrated pest management (IPM) strategy to manage
Varroa, which incorporates both preventative and therapeutic controls. However,
Varroa IPM is complicated and knowledge-intensive. Small-scale beekeepers in
particular seem to have difficulty adopting effective Varroa control strategies, and
suffer especially high rates of colony loss. This study took an interdisciplinary
approach to understanding the adoption of Varroa IPM among small-scale
beekeepers. First, I used surveys and interviews to characterize mite management
strategies among Ohio small-scale beekeepers, and to explore the effect of experience
and risk perception on behavior. Second, as a case study, I took a closer look at the
efficacy and adoption of one complex IPM tool – drone brood removal (DBR) –
through interviews, surveys, and an on-farm trial. Overall, I found no relationship
between beekeeping experience and mite management strategies, but sampling (risk
perception) was associated with the use of “soft” miticides (organic acids/essential
oils) and DBR. I also found that most beekeepers who used DBR combined it with
drone sampling (adjusting DBR based on sampled mite levels), and that labor was the
biggest barrier to DBR use. In the on-farm trial, DBR significantly reduced mites in
year one but not year two. These results suggest that mite management failures
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among small-scale beekeepers are not due to inexperience and may indicate a broader
communication breakdown. They also suggest that risk perception – beekeepers’
understanding that they even have mites – may be a key factor driving adoption of
mite management practices. Finally, they point to the fact that DBR is already being
used in nuanced ways as a combined management and sampling strategy. They
suggest that DBR is not a silver bullet, but can be an effective tool to reduce mites if
used consistently, intensively, and in combination with other management tactics.

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Dedicated to my family

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ACKNOWLEDGEMENTS

This project would not have been possible without help from so many people.
Thanks first to my advisor, Casey Hoy, who was open to advising a project outside
his typical area of research, and who offered endless support, thoughtful edits and a
systems perspective all along the way. Many thanks also to my committee members:
Reed Johnson, who introduced me the beekeeping scene in Ohio and allowed me to
become an honorary member of the Bee Lab – borrowing equipment, attending bee
events, and tagging along for beekeeping activities. And Anna Willow for providing
thoughtful feedback and pushing me to consider the broader social implications of
this research. Thanks also to fellow graduate students – Natalie, Julie, Fred, Matt, as
well as the entomology crew – with whom I’ve had many passionate discussions
about sustainable agriculture and beekeeping, and who made graduate school much
more fun. Many thanks to the beekeepers who volunteered their bees, their
knowledge and their time in order to make the field experiment a reality: Dave Noble,
Phil Young, Laura Urban, Al Blyth, Randall Westfall and Rod and Dru Pritchard.
Thanks to Chia Hua Lin for help with research design and set-up, to Alia Dietsch for
help with survey analysis, and to Meghan Blackson, Sreelakshmi Suresh, Laura
Bond, Natalie Riusech and Andrea Wade for patiently helping me collect data.
Special thanks to Willi for invaluable support and insightful feedback throughout this
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project and to my family, for their support and encouragement in all of my academic
endeavors. Finally, this work would not have been possible without funding from an
Ohio State SEEDS grant.

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VITA

2007……………………Hawken High School, Gates Mills, OH

2007-2011……………...B.A. History, The University of Chicago

2011-2012……………..Administrative Assistant, Common Threads

2012……………………Intern, Coonridge Organic Goat Cheese

2013-2014……………...Research Assistant, Agroecosystem Management Program,
The Ohio State University

2014……………………Farm Manager, Muddy Fork Farm

2014-2016……………..Graduate Fellow, Environmental Science Graduate Program,
The Ohio State University

2016……………………Graduate Teaching Associate, Environmental Science
Graduate Program, The Ohio State University

Fields of Study:

Major Field: Environmental Science
Specialization: Agroecosystem Science

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TABLE OF CONTENTS

ABSTRACT .......................................................................................................................................................... ii
ACKNOWLEDGEMENTS ............................................................................................................................. v
VITA ..................................................................................................................................................................... vii
TABLE OF CONTENTS .............................................................................................................................. viii
LIST OF FIGURES ............................................................................................................................................ x
LIST OF TABLES ............................................................................................................................................. xi
CHAPTER 1 ........................................................................................................................................................ 1
1.1 Introduction ........................................................................................................................................... 1
1.2 The big picture: why we should care about honey bees ......................................................... 6
1.3 Ecology of honey bees and Varroa destructor ........................................................................... 8
1.4 Varroa mite IPM (integrated pest management) .................................................................... 13
1.5 The beekeeping industry ................................................................................................................ 16
1.6 Varroa management among backyard beekeepers ................................................................ 20
1.7 Varroa IPM and the Diffusion of Innovation Framework .................................................. 22
1.8 Drone brood removal ...................................................................................................................... 25
1.9 Research Objectives ........................................................................................................................ 31
CHAPTER 2 ..................................................................................................................................................... 34
2.1 INTRODUCTION ............................................................................................................................... 34
2.2 MATERIALS AND METHODS .................................................................................................... 41
2.2.1 Study Region ................................................................................................................................ 41
2.2.2 Interview Process ........................................................................................................................ 42
2.2.3 Survey Administration ............................................................................................................... 43
2.2.4 Data Analysis ................................................................................................................................ 44
2.3 RESULTS ............................................................................................................................................... 45
2.3.1 Survey Response ......................................................................................................................... 45
2.3.2 Demographic Characteristics .................................................................................................. 46
2.3.3 Characterize mite management strategies (Objective 1) ................................................ 48
2.3.4 Effect of years beekeeping on management and sampling (Objective 2) ................ 55
2.3.5 Effect of sampling on mite management (Objective 3) .................................................. 57
2.4 DISCUSSION ....................................................................................................................................... 59
CHAPTER 3 ..................................................................................................................................................... 63
3.1 INTRODUCTION ............................................................................................................................... 63
3.2 MATERIALS AND METHODS .................................................................................................... 68
3.2.1 Study region .................................................................................................................................. 68
3.2.2 Experimental design ................................................................................................................... 69
3.2.3 Interview process ......................................................................................................................... 73
3.2.4 Survey administration ................................................................................................................ 73
3.2.5 Statistical analysis ....................................................................................................................... 74
3.3 RESULTS ............................................................................................................................................... 76
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3.3.1 Experimental results ................................................................................................................... 76
3.3.2 Interview results ........................................................................................................................... 81
3.3.3 Survey results ............................................................................................................................... 83
3.4 DISCUSSION ....................................................................................................................................... 89
CHAPTER 4 .................................................................................................................................................. 102
LITERATURE CITED ................................................................................................................................ 111
APPENDIX A: INTERVIEW GUIDE ................................................................................................... 120
APPENDIX B: SURVEY INSTRUMENTS ........................................................................................ 123

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