FACTORS AFFECTING MATING, MONITORING AND PHENOLOGY OF GRAPE BERRY MOTH, PARALOBESIA VITEANA, IN MICHIGAN VINEYARDS By Keith Scott Mason A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of Entomology – Doctor of Philosophy 2018 ABSTRACT FACTORS AFFECTING MATING, MONITORING, AND PHENOLOGY OF GRAPE BERRY MOTH, PARALOBESIA VITEANA, IN MICHIGAN VINEYARDS By Keith Scott Mason Paralobesia viteana (Clemens), the grape berry moth (GBM), is a major economic pest of cultivated grapes in Eastern North America. Although pheromone lures and traps are available for monitoring this pest, male moth captures in these traps are not consistent between Michigan grape-growing regions, and male captures decline as the infestation increases through the multiple generations that occur during a season. This makes it difficult to use traps to monitor this pest’s population dynamics and complicates the timing of pest management activities. Substantial regional variation exists in the magnitude of the response of male GBM to sex pheromone-baited traps in Michigan vineyards. Males are readily captured in traps in the southwest region, whereas in the northwest very few males are captured. However grape berry moth larval infestation is found in fruit in both regions. Using Y-tube choice tests and trapping trials with captive females, I determined that males from Southwest and Northwest Michigan responded similarly to the standard pheromone blend, and males did not preferentially choose females from the same population. From these results I conclude that the regional differences in male captures are not due to differential responses of males in these respective areas. I postulate that the reason fewer males are trapped in Northwest Michigan is because the P. viteana population is much smaller than in Southwest Michigan. To test whether seasonal changes in the plant canopy affect captures of male grape berry moth, I manipulated grapevine fruit density or canopy structure in multiple growing seasons, and measured male captures under these conditions. Removal of either 50 or 100% of the fruit clusters from vineyard plots did not consistently affect captures in pheromone traps. In a separate canopy manipulation experiment, I detected significant differences in male captures between unaltered and open canopies for some sample periods, and there was a trend toward numerically more male captures in unaltered than in open canopies. I conclude that fruit presence, fruit density and canopy fullness do not reduce male P. viteana captures late in the season, and thus do not explain the seasonal pattern of development and abundance of this insect. Experiments that measured the frequency, intensity and duration of mating and reproductive behaviors in colonies held under different temperature and photoperiodic conditions were used to determine that temperature is the likely driving force behind the seasonal variation in male P. viteana captures, and thus shapes the observed phenology of this pest. The frequency of male flights, mating and oviposition increased with temperature. This amplified activity helps to explain the intensification of oviposition and subsequent larval feeding damage in vineyards during the summer and early fall when conditions are warm. My data also show the proportion of male flights that occur when females are not receptive to mating is greater at lower temperatures, which helps explain why more males are trapped in the spring when temperatures are cool. Traps baited with lures that contained different quantities of P. viteana sex pheromone were used to determine that the increased amount of pheromone released by lures during hot periods can reduce male captures. My research shows that temperature is an important factor that governs the behaviors associated with mating and reproduction, and also influences the main tool for monitoring this pest, the pheromone trap. Taken as a whole, the effects of temperature on behavior and trapping strongly shape the observedphenology of this pest. For my wonderful family, Julienne, Lindsey and Justin, and my parents, Gail and Charles Mason, I dedicate this dissertation to you with all my love and many thanks for your constant support and encouragement during this process. iv ACKNOWLEDGMENTS First, I thank my wonderful wife Julienne and our beautiful children, Lindsey and Justin. The love and support that you have given to me through these past few years has been a great help and potent motivator to keep me focused and help me finish. I also thank my parents, Gail and Charles Mason, who have been behind me all the way, in mind, body and spirit. I could not have asked for a more engaged guidance committee in Drs. Jim Miller, Jim Smith and Randy Beaudry. I thank you for your ideas and input as my research progressed. You challenged me to think broadly and deeply about all the intricacies of my research projects. This includes proper interpretation of my data, identification of the meaningful implications of my results, and wrapping it all up to present a good story. Rufus Isaacs, my major professor, my boss, my friend. I can’t thank you enough for your patient guidance, sound advice and unwavering support in all my times of need. In all of our interactions, whether as an employee, student or colleague you have made me feel that my ideas and opinions are valuable, and that my work is appreciated. It has been an absolute pleasure, and you have been an incredible influence for me personally and professionally, and I know this is a similar story with others that have passed through your lab. Natalia Botero-Neerdaels, thank you for providing the seed that developed into my own work with grape berry moth. I have also modeled my interactions with collaborating growers after what I learned from you. Zsofia Szendrei, I greatly appreciate your help and guidance with the GC-MS analysis that was an integral part of my research, and thanks also for your assistance with my initial attempts to use PCR. Chris Adams and Phil Fanning have been my in-house support system during my PhD. I thank you both for picking up my slack and for your help, advice, encouragement, friendship and v juicy departmental gossip. Juan Huang and Adam Ingrao, thanks to both of you for the GC-MS methods and advice that I used to analyze pheromone samples. I thank Angie Zhang for help with GIS data, and Bing Tong from the MSU Center for Statistical Training and Consulting for statistical advice. I must thank my Isaacs Lab comrades and the farm staff at Trevor Nichols Research Center and Northwest Michigan Horticulture Research Center for help with experimental set up and collecting data. In particular, I want to thank the student workers that I have had the chance work with and mentor during my PhD: Alexander Apostle, Laura Bizzarri, Jordan Brandel, Therese Costantini, Holly Drankan, Jeremiah Eaton, Matt Hiles, Nolan Jahn, Rachel Labby, Ian McCririe, Josh Paavola, Dan Pickard, Guy Procopio, Trisha Samota, Hayley Sisson, Chris Worst and Zach Yarost. I hope you were able to learn something useful from me; as I know I have learned from you. I have had the good fortune to work with many Michigan grape growers during my time at MSU, and I am thankful for all that you have taught me about the practical side of viticulture, and for allowing me to do research in your vineyards. I thank the following grape producers along with their families and employees that have been an important part of my research: Ed Oxley, Bryan Cronenwett, Rick Brown, Francis Ryan, Bill Mihelich, Chuck Felcyn, Bob and Jason Pagel, Jeff Lemon, Jim Shafer, Larry Mawby, Shady Lane Winery and Leorie Vineyards. I also gratefully acknowledge the Ray and Bernice Hutson Trust Fund, Project GREEEN, The Michigan Grape and Wine Industry Council, The National Grape Cooperative and the US Department of Agriculture for providing funding for my research. vi TABLE OF CONTENTS LIST OF TABLES……………………………………………………………………………….. x LIST OF FIGURES.………………………………………………………………………………xi CHAPTER 1 NATURAL HISTORY, ECONOMIC IMPORTANCE, AND VARIATION IN MONITORING PARALOBESIA VITEANA ……………………………........................................1 Taxonomy and biology…...……………………………………………………………….1 Nomenclature……………………………………………………….......................1 Hosts, habitat and distribution……………………………………………….........1 Life cycle and reproductive biology………………………………………………2 Economic importance....……………………………………………...................................3 History of P. viteana management….………..……..……………………………………..4 The rise of IPM.……...………………………………………...………….…….....5 Monitoring...……….…...……………………………………………………….................7 Thresholds….………………………………………………...…………………....7 The MSU Enviroweather model..………….……………………………..………..7 The importance of pheromones in monitoring….………….………………….......8 The sex pheromone of P. viteana.…..………………………...……...……............8 Geographic variation in sex pheromones..………….….…………………….……………9 Variation between P. viteana populations...….….……………………………......9 Regional variation in other species….………………………………...................10 Seasonal variation in male captures…...……………………………………....................11 The paradox between moth captures and infestation……………….....................11 Plant volatiles as insect attractants...………………………………………..........12 Do grape clusters influence male captures?...........................................................13 Does the grape canopy reduce male captures?.......................................................14 Temperature