Developing Integrated Pest Management Tactics for Squash Vine Borer THESIS Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By Michael Charles McFarland Graduate Program in Entomology The Ohio State University 2017 Committee: Dr. Celeste Welty (advisor) Dr. Reed Johnson Dr. Matt Kleinhenz Copyrighted by Michael Charles McFarland 2017 Abstract Squash vine borer (Melittia cucurbitae; Lepidoptera: Sesiidae) is a serious insect pest of squash and pumpkins in the United States and can cause 100% crop loss in gardens and 25% crop loss in commercial crops. The pest can be controlled by frequent applications of insecticide, but growers are seeking control tactics that are more sustainable. Several chemical and non-chemical tactics for managing M. cucurbitae were evaluated for this project. A field trial was conducted three times to test the use of unharvested zucchini as a trap crop for a cash crop of zucchini. Three factors were compared at each at two levels: harvest status, planting time, and row covers. The infestation rate of M. cucurbitae in earlier plantings was significantly higher than in late plantings. Unharvested plants and row covers had inconsistent effects; infestation was higher in unharvested plants than harvested plants in two of three trials, and infestation was higher in plants started under row covers than no covers in two of three trials. Earlier planted zucchini had higher yields than late plantings, while row covers had no influence on yield. A field trial was conducted in each of two years to test the effect of delayed planting time and row covers on infestation of M. cucurbitae at a garden scale. All of the garden sites had early and late plantings of zucchini, and half of the gardens used row covers. In both years, zucchini planted earlier had higher infestation rates compared to ii later plantings, but the differences were statistically significant in only one year. Zucchini without row covers had higher infestation rates but the differences were not significant either year. Earlier plantings had higher yields than later plantings. A field trial on chemical control of M. cucurbitae on zucchini evaluated the efficacy of three insecticides applied at various frequencies, in each of two years. Insecticide applications began after M. cucurbitae adults were consistently caught in a pheromone trap near the field. In both years, the differences among treatments were not significant for either infestation rate or yield. A laboratory experiment tested the influence of insecticides commonly used for control of M. cucurbitae on two beneficial natural predators: the multicolored Asian lady beetle, Harmonia axyridis (Coleoptera: Coccinellidae), and the insidious flower bug, Orius insidiosus (Hemiptera: Anthocoridae). Predators were exposed to five common garden insecticides indirectly by enclosure on leaves with fresh residues. Mortality was recorded after 24 and 48 hours. Acetamiprid caused significantly higher mortality than the water control for both H. axyridis and O. insidiosus. Permethrin caused significantly higher mortality compared to the water control for H. axyridis. Spinosad did not cause significantly higher mortality compared to the water control for both H. axyridis and O. insidious. Planting earlier, using row covers, and leaving the zucchini unharvested could be the key components for a trap crop to draw M. cucurbitae away from a zucchini cash crop. Delaying planting by four weeks reduces the infestation rates of M. cucurbitae but also reduces the yields of the zucchini. iii Acknowledgments I would like to thank my advisor, Dr. Celeste Welty, for all of her time, advice and support. I also would like to thank my advisory committee for their suggestions throughout my project, and Yi Lu for her help with the statistical analysis. I would like to thank Glenn Mills and the Waterman Agricultural and Natural Resources Laboratory crew for their help with harvesting and plot preparation. I would like to thank my collaborators for letting me use their gardens and for their help recording data. I would like to thank Chad Kramer, Brian Mysonhimer, Susan Ndiaye and James Radl for their help collecting data and setting up plots. I would like to thank the Ohio Vegetable and Small Fruit Research and Development Program for their financial support. I would also like to thank my parents for their support. iv Vita May 2010.......................................................Saline High School May 2014.......................................................B.S. Horticulture, Michigan State University 2014 to 2016 ..................................................Graduate Teaching Associate, Center for .......................................................................Life Sciences Education 2016 to present ..............................................Graduate Teaching Associate, Department of Entomology, The Ohio State University Fields of Study Major Field: Entomology v Table of Contents Abstract .............................................................................................................................ii Acknowledgments ............................................................................................................iv Vita......................................................................................................................................v List of Figures .................................................................................................................. ix List of Tables.....................................................................................................................xi Chapter 1: Squash Vine Borer: Introduction and Literature Review.........................1 1.1 Introduction..................................................................................................................1 1.2 Background..................................................................................................................1 1.2.1 Range and Hosts ...........................................................................................1 1.2.2 Life cycle ......................................................................................................2 1.2.3 Monitoring ....................................................................................................3 1.2.4 Chemical control............................................................................................3 1.2.5 Biological control..........................................................................................4 1.2.6 Compatibility of biological control and chemical control ............................5 1.2.7 Compatibility of chemical control to pollinators ..........................................6 1.2.8 Mechanical control........................................................................................7 1.2.9 Cultural control......................................................................................8 1.3 Rationale and significance ........................................................................................10 1.4 References ..................................................................................................................12 vi Chapter 2: Evaluating factors affecting zucchini as a trap crop for squash vine borer..................................................................................................................................16 2.1 Introduction ...............................................................................................................16 2.2 Materials and Methods .............................................................................................18 2.3 Results ........................................................................................................................20 2.4 Discussion...................................................................................................................22 2.5 References ..................................................................................................................25 2.6 Figures ........................................................................................................................27 2.7 Tables..........................................................................................................................31 Chapter 3: Delayed planting for squash vine borer management in home garden squash................................................................................................................................33 3.1 Introduction ...............................................................................................................33 3.2 Materials and Methods .............................................................................................35 3.3 Results ........................................................................................................................38 3.4 Discussion...................................................................................................................39 3.5 References ..................................................................................................................41 3.6 Figures ........................................................................................................................43 3.7 Tables..........................................................................................................................47