Final Report

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ABSTRACT This project advanced the science and technology in a broad range of disciplines from pathogen aquatic biology to applied microbial ecology, hydrology, and socio-economics of recycling irrigation water. Some of these advancements have already enabled early adopters to build pathogen mitigation features into water recycling systems and implement best irrigation practices for improved horticultural profitability while reducing their environmental footprint. This project also educated next generation leaders in water reuse, strengthened FINAL REPORT industry partnerships, and built a broad international network of SCRI Project (Agreement #: 2010-51181-21140): scientists working on irrigation pathogen issues, which all will Integrated Management of Zoosporic Pathogens and continue promoting the green Irrigation Water Quality for a Sustainable Green Industry industry’s long-term sustainability in the years to come.

Cover photo: The first annual project meeting at the Virginia Tech’s Hampton Roads Agricultural Research and Extension Center in Virginia Beach, VA (October 21, 2010)

Contents

PRODUCT HIGHLIGHT ...... 1 A Comprehensive Resource on Biology, Detection and Management of Plant Pathogens in Irrigation Water ...... 3 A 14-Session Webinar Series on Irrigation Pathogens and Water Quality ...... 4 An Outreach Website Highlighting the Project Vision, Mission, Approaches, Research/ Educational Programs, and Major Accomplishments ...... 5 An Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture ... 6 PRECIOUS MOMENTS ...... 7 Cutting-Edge Research and Education Programs ...... 9 Industry Partnerships ...... 11 Professional Development for Graduate Students, Postdocs, and Summer Interns ...... 11 Annual Project Meetings ...... 12 A BRIEF ACCOUNT OF ACTIVITIES AND ACCOMPLISHMENTS ...... 13 Project Director ...... 15 Co-Project Directors ...... 15 Project Team Members ...... 15 Advisory Panel ...... 16 Major Partners ...... 16 Major Collaborating Nurseries and Greenhouses (Key Contacts) ...... 16 Major Institutional Partners (Key Contacts) ...... 17 Major Collaborators and Institutions ...... 18 Target Audience ...... 18 Non-Technical Summary ...... 18 Products ...... 19 Dissertations and Theses ...... 19 Book ...... 19 Book Chapters ...... 19 Refereed Journal Articles ...... 21 Abstracts ...... 24 Invited Lectures and Contributions to Professional Meetings ...... 26 Outreach Website ...... 28

Survey Instruments ...... 28 Protocols ...... 28 Webinars ...... 31 Extension and Outreach Presentations ...... 32 Symposia Organized and Moderated...... 33 Physical Collections ...... 33 Major Goals of the Project ...... 34 What Was Accomplished under These Goals? ...... 35 What Opportunities for Training and Professional Development Has the Project Provided? ..... 37 Agricultural and Applied Economics, Virginia Tech ...... 37 Hampton Roads AREC, Virginia Tech ...... 37 Pennsylvania State University ...... 38 How Have the Results Been Disseminated to Communities of Interest? ...... 39 Outreach Website: Irrigation Pathogens and Water Quality (http://www.irrigation- pathogens.ppws.vt.edu/index.php) ...... 39 Annual Project Meetings and Web Conferences ...... 39 Extension and Outreach Presentations ...... 39 Webinar Series: Irrigation Pathogens and Water Quality ...... 40 One-on-One Consultations with Growers ...... 40 Online Knowledge Center: Irrigation Water Management for Ornamental Horticulture (www.extension.org) ...... 40 Scientific Publications ...... 40 Lectures and Presentations ...... 41 International Symposia ...... 41 The Book: Biology, Detection and Management of Plant Pathogens in Irrigation Water ...... 41 What Do You Plan to Do during the Next Reporting Period to Accomplish the Goals? ...... 41

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PRODUCT HIGHLIGHT

A Comprehensive Resource on Biology, Detection and Management of Plant Pathogens in Irrigation Water

A 14-Session Webinar Series on Irrigation Pathogens and Water Quality

An Outreach Website Highlighting the Project Vision, Mission, Approaches, Research/ Educational Programs, and Major Accomplishments

An Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture

PRECIOUS MOMENTS

Cutting-Edge Research and Education Programs Row 1 (from left to right): Gary Moorman surveying greenhouse floor, Carla Lanze collecting biofilm from an ebb and flow system, Maria Burgos-Garay taking water samples; Row 2: Ping Kong investigating pathogen aquatic biology, Xiao Yang examining morphology of a new Phytophthora taxon, Warren Copes baiting in a recycling irrigation reservoir; Row 3: John Lea-Cox setting up an automatic weather station, Thomas Wilchynski connecting a water quality monitoring unit to a telemetry system, Patricia Richardson maintaining water quality monitoring stations and downloading data; Row 4: Patricia working with an YSI tech support agent on water quality data communication via satellites, a computer screenshot showing real-time water quality readings at a collaborating nursery, Pete Schultz and other Center staff helping load test plants to a truck for field demonstration plots

Industry Partnerships Row 1 (from left to right): Bill Daughtry of Lancaster Farms assisting in Decagon unit installation, Dewayne Stables of Lancaster Farms working with John Lea-Cox on tracking water quality real-time, Dewayne and his crew taking sediment samples; Row 2: Bob Black and his crew of Bennett’s Creek Nursery assisting Decagon instrument installation for weather and water quality monitoring, Sean McGrory of Colesville Nursery digging a hole for telemetry system installation; Row 3: Douglas Eller presenting at an annual project meeting, Lee Heyl working with Andrew Ristvey at Homestead Growers, Grower’s boat made available for pathogen baiting and water quality monitoring in GreenForest Nursery; Row 4: Farm truck moving test plants for field demonstration, layout of field demonstration plots designed and established by John Lancaster and his crew at Bennett’s Creek Nursery, and growers at Lancaster Farms assisting field demonstration plot setup; Row 5: Bill and his Crew at Lancaster Farms, John Lancaster and his associates at Bennett’s Creek Nursery working with Chuan Hong in preparing and delivering the chlorination webinar, Dewayne discussing with Walter Wohanka on horticulture and water decontamination technology

Professional Development for Graduate Students, Postdocs, and Summer Interns Row 1 (from left to right): Haibo Zhang reporting recycled water quality analysis and modeling, Wei Hao presenting an improved heat treatment for water decontamination, Cafa Giovanni investigating bacterial diversity in recycling irrigation reservoirs (RIR); Row 2: Mrina Nikrad getting ready for a presentation on her study of ammonia-oxidizing archaea and bacteria in RIRs, Michael Pistinizi presenting his studies at an annual project meeting, David Hartter working with Kevin Boyle to get ready for a presentation on consumers’ survey; Row 3: Alyssa Cultice and Xiang Cao presenting, Gwen Rees and Nicole D’Alessio attending annual project meetings, respectively

Annual Project Meetings 2010 (Row 1 from left to right): Kevin Boyle presenting the Agricultural Economics Team’s plan, continuing discussion during a break, touring sustainable gardens in the evening; 2011 (Row 2): John Lea-Cox reporting the University of Maryland Team’s progress, Marc Teffeau commenting on the importance of water reuse to the nation’s horticulture industry, Gary Chastagner reviewing water issues in Washington; 2012 (Row 3): Darrell Bosch, Alyssa Cultice, James Pease presenting growers’ survey draft, Charles Parkerson sharing the thoughts behind his water recycling systems, Chuan Hong refreshing the Year 3 targets; 2013 (Row 4): James, Darrell reporting the growers’ survey followed by group discussion; 2015 (Row 5): Gary Moorman, Ping Kong and Warren Copes presenting water recycling system designs with pathogen mitigation features

A BRIEF ACCOUNT OF ACTIVITIES AND ACCOMPLISHMENTS

Project Director

Chuanxue Hong (Professor of Plant Pathology, Virginia Tech)

Co-Project Directors

Gary W. Moorman (Professor of Plant Pathology, Pennsylvania State University) John D. Lea-Cox (Professor of Horticulture, University of Maryland) Kevin J. Boyle (Professor of Agricultural and Applied Economics, Virginia Tech) Darrell Bosch (Professor of Agricultural and Applied Economics, Virginia Tech) James Pease (Professor of Agricultural and Applied Economics, Virginia Tech) Warren E. Copes (Research Plant Pathologist, USDA-ARS) Ping Kong (Research Scientist of Molecular Plant Pathology, Virginia Tech) Andrew Ristvey (Associate Professor of Horticulture, University of Maryland) Belinda Carroll (Educational Manager, Virginia Tech) David Ross (Professor of Agricultural Engineering, University of Maryland) Michael E. Stanghellini (Professor of Plant Pathology, University of California, Riverside) Boris A. Vinatzer (Associate Professor of Plant Pathology, Virginia Tech) Edward Weiss (Professor of Biology, Christopher Newport University)

Project Team Members

Lauren Achtemeier (Summer Intern, Virginia Tech) Bruk Belayneh (Research Associate, University of Maryland) Ailing Ben (Visiting Scientist, Virginia Tech) Maria Burgos-Garay (Graduate Student and Postdoc Associate, Pennsylvania State University) Ava Butler (Administrative Assistant, Virginia Teck) Nicole Calderon (Summer Intern, Virginia Tech) Xiang Cao (Graduate Student, Virginia Tech) Joshua Chambers (Web Design Specialist, Virginia Tech) Venkataramana Chaparral (Visiting Scientist, Virginia Tech) Alyssa Cultic (Graduate Student, Virginia Tech) Nicole D’Alessio (Graduate Student, Virginia Tech) Laura del so Bautista-Jalon (Graduate Student, Pennsylvania State University) Carl Estes (Information Technologist, Virginia Tech) Nathaniel Ferraro (Graduate Student, Virginia Tech) Cafa Giovanni (Postdoc Associate, Virginia Tech) David Hartter (Graduate Student, Virginia Tech) Wei Hao (Graduate Student and Postdoc Associate, Virginia Tech) Kevin Hu (Summer Intern, Virginia Tech) Sandra Johansson (Research Assistant, Virginia Tech) Carla E. Lanze (Graduate Student, Pennsylvania State University) Phaedra Lewis (Sr. Post-Award Administrator, Virginia Tech) Lesley Mitchell (Grants Specialist, Virginia Tech) Mrina Nikrad (Postdoc Associate, Virginia Tech) Heather Olson (Postdoc Associate, Virginia Tech)

Michael Pistininzi (Summer Intern, Virginia Tech) Gwendolen Rees (Graduate Student, Virginia Tech) Patricia Richardson (Research Specialist Sr., Virginia Tech) Andrew Rotzin (Summer Intern, Virginia Tech) Peter Schultz (Center Director, Virginia Tech) Adam Sleeper (Agricultural Research Supervisor, Virginia Tech) Marcia Stefani (Research Specialist Sr., Virginia Tech) Neal Vines (Center Director, Virginia Tech) Thomas Wilchynski (Mechanic and Safety Officer, Virginia Tech) Craig Woods (Center Director, Virginia Tech) Weibin Xu (Graduate Student, Virginia Tech) Xiao Yang (Graduate Student and Postdoc Associate, Virginia Tech) Haibo Zhang (Postdoc Associate, Virginia Tech)

Advisory Panel

Joseph Albano (Director, Horticultural Research Institute, AmericanHort) Joseph Bischoff (Director, Regulatory and Government Relation, AmericanHort) Daniel Batson (President, GreenForest Nursery, MS) David Conkle (Manager, Flowerwood Nursery at Mobile, AL) Gary Cooper (President, Cooper’s Landscape Management, VA) Roger Esbenshade (Owner, Esbenshade’s Greenhouses, PA) Samul Gaddy (President, Colesville Nursery, VA) Jody Jellison (Associate Director, VA Agricultural Experiment Station) Saied Mostaghimi (Director, VA Agricultural Experiment Station) John Lancaster (Sr. Vice President, Bennett’s Creek Nursery, VA) Mike Leubecker (Manager, Tidal Creek Growers at Davidsonville, MD) Jeff Miller (Executive Director, VA Nursery and Landscape Association) Charles Parkerson (Founder, Lancaster Farms, VA) John Pursell (President, Moon Nurseries, MD) Edward Riddle (Owner, Homestead Growers, MD) Lin Schmale (Director, Government Relation, Society of American Florists) Doug Schmidt (Manager, Flowerwood Nursery at Mobile, AL) Daniel Schwalm (Owner, Schwalm’s Greenhouses, PA) Gerald Teeuwen (Owner, Teeuwen Greenhouses, VA) Marc Teffeau (Director, Horticultural Research Institute, AmericanHort)

Major Partners

Major Collaborating Nurseries and Greenhouses (Key Contacts) Bennett’s Creek Nursery, VA (Robert Black, Joshua Pickett, Matthew Sawyer) Colesville Nursery, VA (Sean McGrory) Eastern Shore Nursery of Virginia, VA (Robin Rinaca) Esbenshade’s Greenhouses, PA (Roger Esbenshade) Flowerwood Nursery at Mobile, AL (David Conkle, Doug Schmidt) Evergreen Berry Farm, CT (Robert Alex)

GreenForest Nursery, MS (Daniel Batson) Homestead Growers, MD (Lee Heyl, Oliver Storm) Lancaster Farms, VA (Chris Brown, Bill Daughtry, Shawn Jones, Dewayne Stables, Hank Thornburg) Moon Nurseries, MD (Doug Eller, Brad Moran) Riverbend Nursery, VA (James Snyder, Isaac Brantingham) Schwalm’s Greenhouses, PA (Daniel Schwalm) Tidal Creek Growers, MD (Mike Leubecker)

In-kind contributions to this project as reported from some collaborating growers during the first 4 years (from September 2010 to August 2014)

Actual total Nursery/ Anticipated contributions State Greenhouse 5-year total by the end of year 4 Balance

Alabama Flowerwood $47,035.00 $55,250.40 $8,215.40

Maryland Homestead/ $64,125.00 $73,783.00 $9,658.00 Tidal Creek

Maryland Moon $95,510.00 $90,797.80 -$4,712.20

Mississippi GreenForest $50,690.00 $217,544.20 $166,854.20

Virginia Bennett's Creek $152,000.00 $130,883.00 -$21,117.00

Virginia Colesville $72,215.00 $50,062.00 -$22,153.00

Virginia Lancaster Farms $229,555.00 $268,782.00 $39,227.00

Pennsylvania Esbenshade $29,360.00 $7,916.00 -$21,444.00

Pennsylvania Schwalm $12,500.00 $20,092.50 $7,592.50

Total $752,990.00 $915,110.90 $162,120.90

Major Institutional Partners (Key Contacts) AmericanHort (Joseph Albano, Joseph Bischoff, Marc Teffeau) Society of American Florists (Lin Schmale) Crossnore Ornamental Plant Pathologists and Entomologists (Michael Benson) American Phytopathological Society National Plant Diagnostic Network Virginia Nursery and Landscape Association (Jeff Miller) Virginia Cooperative Extension Other local extension and industry networks

Major Collaborators and Institutions

Carmen Büttner, Professor of Virology, Humboldt-Universität zu Berlin, Germany Gary Chastagner, Professor of Plant Pathology, Washington State University Mark Dasenko, Core Lab Technician, Oregon State University Marianne Elliott, Research Scientist of Plant Pathology, Washington State University Amy Fulcher, Assistant Professor, University of Tennessee Brent Kronmiller, Bioinformatics Analyst, Oregon State University Willem A. Man in 't Veld, Plant Pathologist, National Plant Protection Services, the Netherlands James Owen, Assistant Professor of Horticulture, Virginia Tech Allen Owings, Professor of Horticulture, Louisiana State University Matthew Peterson, Computational Scientist, Oregon State University Adelaide Rhodes, Trainer of Bioinformatics, Oregon State University Aaron Trippe, Core Lab Technician, Oregon State University Brett Tyler, Professor and Director of Genome Research and Biocomputing, Oregon State University Kelly Vining, Assistant Professor of Horticulture, Oregon State University Walter Wohanka, Professor of Horticulture, Geisenheim University, Germany

Target Audience

Nursery growers and greenhouse producers Garden centers, retailers, and landscapers Agricultural industry scientists and consultants Extension specialists and agents Plant disease diagnosticians, regulatory personnel Undergraduate and graduate students, postdoctoral associates Educators, horticulturists, mycologists, and researchers Conservation biologists Policy makers

Non-Technical Summary

This SREP project addresses three SCRI focus areas and aims to improve and maintain the health of nursery and floral crops from the time of production to delivery to the consumer, to protect water quality and to increase water use efficiency by the green industry. The ultimate goals are to move horticultural production and distribution towards greater sustainability and enable nurseries and greenhouses to better compete in global markets. Supporting objectives are to (1) characterize zoosporic pathogens found in irrigation systems and assess their potential impact on ornamental crop health; (2) understand water quality dynamics, develop guidelines to assist irrigation managers in improving crop quality and productivity, and assess the environmental benefits of increased water recycling practices; (3) significantly increase the understanding of the aquatic biology of Phytophthora and Pythium species and develop protocols for risk assessment and mitigation of these pathogens in irrigation systems; (4) identify and enhance naturally-occurring pathogen-suppressing microbes in reservoirs; (5) assess the changes in production costs and revenue enhancements when the resultant knowledge and technologies

are implemented as best management practices (BMPs); and (6) develop and use an online knowledge center to deliver information and education programs and facilitate BMP implementation. This project will increase the profitability and sustainability of the green industry, enhance the aesthetic value of recreational parks and landscapes, and improve consumer satisfaction with the plants they purchase. It will reduce the risk of dissemination of quarantine pathogens (e.g., Phytophthora ramorum) through trade of ornamental plant stocks. These benefits will extend to other specialty crop producers facing similar crop health and water issues.

Products

Dissertations and Theses

1. Burgos-Garay, M. L. 2013. Effect of heterotrophic bacterial communities on Pythium spp. in recycled irrigation water. Ph.D. dissertation. The Pennsylvania State University, University Park, PA 2. Cultice, A. 2013. Horticultural producers' willingness to adopt water recirculation technology in the Mid-Atlantic region. M.S. Thesis. Virginia Tech, Blacksburg, VA 3. D’Alessio, N. 2015. Segmentation of the market for labeled ornamental plants by environmental preferences: A latent class analysis. M.S. Thesis. Virginia Tech, Blacksburg, VA 4. Ferraro, N. 2015. Economic analysis of recapturing and recycling irrigation techniques on horticulture nurseries. M.S. Thesis. Virginia Tech, Blacksburg, VA 5. Hao, W. 2012. A potential energy-efficient heat treatment and its biological mechanisms. Ph.D. Dissertation, Virginia Tech, Blacksburg, VA 6. Hartter, D. 2012. Understanding consumers’ ornamental plant preferences for disease- free and water conservation labels. M.S. Thesis. Virginia Tech, Blacksburg, VA 7. Lanze, C. E. 2015. Characterization of Pythium and Phytopythium species frequently found in irrigation water. M. S. thesis. The Pennsylvania State University, University Park, PA 8. Yang, X. 2014. New species and phylogeny of the genus Phytophthora. Ph.D. Dissertation. Virginia Tech, Blacksburg, VA

Book

1. Hong, C. X., Moorman, G. W., Wohanka, W., and Büttner, C. (eds.) 2014. Biology, Detection, and Management of Plant Pathogens in Irrigation Water. American Phytopathological Society, St. Paul, MN, USA

Book Chapters

1. Büttner, C., Hong, C. X., Moorman, G. W., and Wohanka, W. 2014. Preface. In Biology, Detection, and Management of Plant Pathogens in Irrigation Water. C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.) American Phytopathological Society, St. Paul, MN, USA

2. Copes, W. E., Barbeau, B., and Chastagner, G. A. 2014. Chlorine dioxide for irrigation water treatment. Pages 251-266 In Biology, Detection, and Management of Plant Pathology in Irrigation Water. C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.) American Phytopathological Society, St. Paul, MN, USA 3. Elmer, W. H., Buck, J., Ahonsi, M. O., and Copes, W. E. 2014. Emerging technologies for irrigation water treatment. Pages 289-302 In Biology, Detection, and Management of Plant Pathology in Irrigation Water. C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.) American Phytopathological Society, St. Paul, MN, USA 4. Hao, W., Vinatzer, B. A., and Hong, C. X. 2014. Pasteurization for irrigation water treatment. Pages 187-195 In Biology, Detection, and Management of Plant Pathogens in Irrigation Water. C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.) American Phytopathological Society, St. Paul, MN, USA 5. Hong, C. X. 2014. Management of plant pathogens in irrigation water. Pages 74-75 In Compendium of Rhododendron and Azalea Diseases. R. Linderman, and D. M. Benson (eds.) American Phytopathological Society, St. Paul, MN, USA 6. Hong, C. X. 2014. Developing a facility and production plan for management of plant pathogens in irrigation water. Page 75 In Compendium of Rhododendron and Azalea Diseases. R. Linderman, and D. M. Benson (eds.) American Phytopathological Society, St. Paul, MN, USA 7. Hong, C. X. 2014. Selecting a water treatment technology for control of plant pathogens in irrigation water. Pages 75-76 In Compendium of Rhododendron and Azalea Diseases. R. Linderman, and D. M. Benson (eds.) American Phytopathological Society, St. Paul, MN, USA 8. Hong, C. X. 2014. Component analysis of irrigation water in plant disease epidemiology. Pages 111-121 In Biology, Detection, and Management of Plant Pathogens in Irrigation Water, C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.) American Phytopathological Society, St. Paul, MN, USA 9. Hong, C. X. 2014. Economic threshold of plant pathogen in irrigation water. Pages 175- 183 In Biology, Detection, and Management of Plant Pathogens in Irrigation Water, C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.) American Phytopathological Society, St. Paul, MN, USA 10. Hong, C. X., Büttner, C., Moorman, G. W., and Wohanka, W. 2014. A partial list of plant pathogens found in water to date. Pages 389-411 In Biology, Detection, and Management of Plant Pathogens in Irrigation Water, C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.), American Phytopathological Society, St. Paul, MN, USA 11. Ivors, K. L., and Moorman, G. W. 2014. Oomycete plant pathogens in irrigation water. Pages 57-64 In Biology, Detection, and Management of Plant Pathogens in Irrigation Water. C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.) American Phytopathological Society, St. Paul, MN, USA 12. Kong, P., and Lea-Cox, J. D. 2014. Water quality dynamics and influences on pathogen mitigation in irrigation reservoirs. Pages 333-346 In Biology, Detection, and Management of Plant Pathology in Irrigation Water. C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.) American Phytopathological Society, St. Paul, MN, USA

13. Lea-Cox, J. D., and Ross, D. S. 2014. Water management to minimize pathogen movement in containerized production systems. Pages 377-388 In Biology, Detection, and Management of Plant Pathology in Irrigation Water. C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.) American Phytopathological Society, St. Paul, MN, USA 14. Moorman, G. W. 2014. Irrigation water and the health of greenhouse crops. Pages 23-29 In Biology, Detection, and Management of Plant Pathogens in Irrigation Water. C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.) American Phytopathological Society, St. Paul, MN, USA 15. Moorman, G. W., Gevens, A. J., Granke, L. L., Hausbeck, M. K., Hendricks, K., Roberts, P. D., and Pettitt, T. R. 2014. Sources and distribution systems of irrigation water and their potential risks for crop health. Pages 3-11 In Biology, Detection, and Management of Plant Pathogens in Irrigation Water. C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.) American Phytopathological Society, St. Paul, MN, USA 16. Ristvey, A. G. and Moorman, G. W. 2014. An integrated approach to minimizing plant pathogens in runoff water from containerized production systems. Pages 365-375 In Biology, Detection, and Management of Plant Pathogens in Irrigation Water. C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.) American Phytopathological Society, St. Paul, MN, USA 17. Ross, D. S. 2014. Water resources and designs of recycling irrigation system for healthy crops. Pages 321-332 In Biology, Detection, and Management of Plant Pathology in Irrigation Water. C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds.) American Phytopathological Society, St. Paul, MN, USA

Refereed Journal Articles

1. Burgos-Garay, M., Hong, C. X., and Moorman, G. W. 2014. Complex heterotrophic bacterial interactions with plant pathogenic Pythium in recycled irrigation water. HortScience 49:961-967 2. Copes, W. E., Yang, X., and Hong, C. X. 2015. Phytophthora species recovered from irrigation reservoirs in Mississippi and Alabama nurseries and pathogenicity of three new species. Plant Disease 99: dx.doi.org/10.1094/PDIS-11-14-1197-RE 3. Garzón, C. D., Molineros, J. E., Yánez, J. M., Flores, F. J., Jiménez-Gasco, M. M., and Moorman, G. W. 2011. Sublethal doses of mefenoxam enhance Pythium damping-off of geraniums. Plant Disease 95: 1233-1238 4. Ghimire, S. R., Richardson, P. A., Kong, P., Hu, J. H., Lea-Cox, J. D., Ross, D. R., Moorman, G. W., and Hong, C. X. 2011. Distribution and diversity of Phytophthora species in nursery irrigation reservoir adopting water recycling system during winter months. Journal of Phytopathology 159:713-719 5. Hao, W., Ahonsi, M. O., Vinatzer, B. A., and Hong, C. X. 2012. Inactivation of Phytophthora and bacterial species in water by a potential energy-saving heat treatment. European Journal of Plant Pathology 134:357-365 (online at doi: 10.1007/s10658-012- 9994-4) 6. Hao, W., and Hong, C. X. 2014. Heat treatment induced bacterial changes in irrigation water and their implications for plant disease management. World Journal of

Microbiology and Biotechnology 30:1591-1601 (online version at doi: 10.1007/s11274- 013-1583-y) 7. Hao, W., Richardson, P. A., and Hong, C. X. 2010. First report of foliar blight of Catharanthus roseus caused by Phytophthora tropicalis in Virginia. Plant Disease 94:274 8. Hong, C. X., Gallegly, M. E., Richardson, P. A., and Kong, P. 2011. Phytophthora pini Leonian resurrected to distinct species status. Mycologia 103:351-360 9. Hong, C. X., Gallegly, M. E., Richardson, P. A., Kong, P., Moorman, G. W., Lea-Cox, J. D., and Ross, D. S. 2010. Phytophthora hydropathica, a new pathogen identified from irrigation water, Rhododendron catawbiense and Kalmia latifolia. Plant Pathology 59:913-921 10. Hong, C. X., Richardson, P. A., Hao, W., Ghimire, S. R., Kong, P., Moorman, G. W., Lea-Cox, J. D., and Ross, D. S. 2012. Phytophthora aquimorbida sp. nov. and Phytophthora taxon ‘aquatilis’ recovered from irrigation reservoirs and a stream in Virginia, USA. Mycologia. 104:1097-1108 11. Kong, P. 2012. Carbon dioxide as a potential water disinfectant for Phytophthora disease risk mitigation. Plant Disease http://dx.doi.org/10.1094/PDIS-09-12-0844-RE 12. Kong, P., and Hong, C. X. 2010. Zoospore density-dependent behaviors of Phytophthora nicotianae are autoregulated by extracellular products. Phytopathology 100:632-637 13. Kong, P., and Hong, C. X. 2014. Oxygen stress reduces zoospore survival of Phytophthora species in a simulated aquatic system. BMC Microbiology http://www.biomedcentral.com/1471-2180/14/124 14. Kong, P., Lea-Cox, J. D., and Hong, C. X. 2012. Effect of electrical conductivity on survival of Phytophthora alni, P. kernoviae and P. ramorum in a simulated aquatic environment. Plant Pathology 61:1179–1186 15. Kong, P., Lea-Cox, J. D., Moorman, G. W., and Hong, C. X. 2012. Survival of Phytophthora alni, P. kernoviae and P. ramorum in a simulated aquatic environment at different levels of pH. FEMS Microbiology Letters 332:54-60 16. Kong, P., Lee, B. W. K., Zhou, Z. S., Bhalla, R., and Hong, C. X. 2010. Zoosporic plant pathogens produce bacterial autoinducer-2 that affects Vibrio harveyi quorum sensing. FEMS Microbiology Letters 303:55-60 17. Kong, P., Tyler, B. M., Richardson, P. A., Lee, B. W. K., Zhou, S. H., and Hong, C. X. 2010. Zoospore interspecific signaling promotes plant infection by Phytophthora species. BMC Microbiology http://www.biomedcentral.com/1471-2180/10/313 18. Lanze, C. E., Burgos-Garay, M., Hong, C. X., and Moorman, G. W. 201X. The community of Pythium and Phytopythium species that inhabit two commercial Pennsylvania recycled irrigation water greenhouse tanks. Plant Disease (accepted) 19. Man in 't Veld, W. A., Rosendahl, K. C. H. M., and Hong, C. X. 2012. Phytophthora Xserendipita sp. nov., a new species generated by natural hybridization. Mycologia 104:1390-1396 (Online at doi:10.3852/11-272) 20. Pistininzi, M., Weiss, E., Achtemeier, L., and Hong, C. X. 2013. Zoospore production biology of pythiaceous plant pathogens. Journal of Phytopathology 162:69-80 (Online at doi: 10.1111/jph.12154) 21. Yang, X., Balci, Y., Brazee, N. J., Lyod, A. L., and Hong, C. X. 2015. Phytophthora intercalaris sp. nov., a new species recovered from stream and irrigation water in eastern

United States. International Journal of Systematic and Evolutionary Microbiology (accepted) 22. Yang, X., Copes, W. E., and Hong, C. X. 2013. Phytophthora mississippiae sp. nov., a new species recovered from irrigation reservoirs at a plant nursery in Mississippi. Journal of Plant Pathology and Microbiology http://dx.doi.org/10.4172/2157- 7471.1000180 23. Yang, X., Copes, W. E., and Hong, C. X. 2014. Two novel species representing a new clade and cluster of Phytophthora species. Fungal Biology 118:72-82 24. Yang, X., Gallegly, M. E., and Hong, C. X. 2014. A new high-temperature tolerant species in the clade 9 of the genus Phytophthora: P. hydrogena sp. nov. Mycologia 106:57-65 (online version at doi:10.3852/13-043) 25. Yang, X., and Hong, C. X. 2013. Phytophthora virginiana sp. nov., a high-temperature tolerant species from irrigation water in Virginia. Mycotaxon 126:167-176 (online version at http://dx.doi.org/10.5248/126.167) 26. Yang, X., and Hong, C. X. 2014. Halophytophthora fluviatilis sp. nov. from freshwater in Virginia. FEMS Microbiology Letters 352:230-237 (online version at doi: 10.1111/1574- 6968.12391) 27. Yang, X., Kong, P., and Hong, C. X. 2013. Evaluation of fungicide drenches for control of Phytophthora root rot of petunia, 2012. Plant Disease Management Reports 7:OT002 28. Yang, X., Richardson, P. A., Ghimire, S. R., Kong, P., and Hong, C. X. 2012. Phytophthora hedraiandra detected from irrigation water at a perennial plant nursery in Virginia. Plant Disease 96:915 29. Yang, X., Richardson, P. A., and Hong, C. X. 2013. Evaluation of nonregistered fungicide for control of rose downy mildew, 2012. Plant Disease Management Reports 7:OT001 30. Yang, X., Richardson, P. A., and Hong, C. X. 2014. Phytophthora×stagnum nothosp. nov., a new hybrid from irrigation reservoirs at ornamental plant nurseries in Virginia. PLoS One at http://dx.plos.org/10.1371/journal.pone.0103450 31. Yang, X., Richardson, P. A., Kong, P., and Hong, C. X. 2013. Fungicidal control of Phytophthora aerial blight on annual vinca in Virginia, 2012. Plant Disease Management Reports 7:OT005 32. Yang, X., Richardson, P. A., Olson, H. A., and Hong, C. X. 2013. Root and stem rot of begonia caused by Phytopythium helicoides in Virginia. Plant Disease 97:1385 33. Zhang, H., Richardson, P. A., Belayneh, B. E., Ristvey, A. G., Lea-Cox, J. D., Copes, W. E., Moorman, G. W., and Hong, C. X. 2015. Characterization of water quality in stratified nursery recycling irrigation reservoirs. Agricultural Water Management 160:76-83 34. Zhang, H., Richardson, P. A., Belayneh, B. E., Ristvey, A. G., Lea-Cox, J. D., Copes, W. E., Moorman, G. W., and Hong, C. X. 2015. Comparative analysis of water quality between the runoff entrance and middle of recycling irrigation reservoirs. Water 7:3861- 3877 35. Zhang, H., Richardson, P. A., Belayneh, B. E., Ristvey, A. G., Lea-Cox, J. D., Copes, W. E., Moorman, G. W., and Hong, C. X. 2015. Recycling irrigation reservoir stratification and implications for crop health and production. Journal of the American Water Resources Association (accepted)

36. Cafà, G., and Hong, C. X. 2015. Distinct bacterial community composition in an emerging ecosystem of agricultural runoff water containment basins. Applied and Environmental Microbiology (submitted) 37. Kong, P., and Hong, C. X. 2015. Environmental bacteria promote infection of host and nonhost plants by Phytophthora species. ISME Journal (submitted) 38. Kong, P., and Hong, C. X. 2015. Genetic diversity and abundance of cyanobacteria and associated microbes in agricultural runoff containment reservoirs. Journal of Environmental Management (submitted) 39. Kong, P., and Hong, C. X. 2015. Seasonal dynamics of cyanobacterial and associated microbial communities in a multi-reservoir recycling irrigation system. Applied and Environmental Microbiology (submitted) 40. Nikrad, M., and Hong, C. X. 2015. Diversity and abundance of ammonia-oxidizing archaea and bacteria in recycled irrigation waters in eastern and central Virginia. Applied and Environmental Microbiology (submitted) 41. Yang, X., and Hong, C. X. 2015. Comparative analysis of Phytophthora, Phytopythium and Pythium diversity among different depths of sediments in an agricultural runoff sedimentation reservoir. Plant Pathology (submitted) 42. Zhang, H., Richardson, P. A., Belayneh, B. E., Ristvey, A. G., Lea-Cox, J. D., Copes, W. E., Moorman, G. W., and Hong, C. X. 2015. Dominance and crop production implications of alkaline pH in recycling irrigation reservoirs. Irrigation Science (submitted)

Abstracts

1. Burgos-Garay, M. L., Edson, J., and Moorman, G. W. 2012. Influence of Pythium aphanidermatum, P. irregulare, and P. cryptoirregulare on the bacterial community in recycled irrigation water. Phytopathology 102:S1.2 2. Burgos-Garay, M. L., and Moorman, G. W. 2011. Influence of Pythium aphanidermatum, P. irregulare, and P. cryptoirregulare on the bacterial community in recycled irrigation water. Phytopathology 102:S23 3. Burgos-Garay, M. L., and Moorman, G. W. 2011. Effect of microbial communities in recycled irrigation water on the development of three Pythium species. Phytopathology 101:S258 4. Copes, W. E., Yang, X., and Hong, C. X. 2015. Phytophthora species recovered from irrigation reservoirs in Mississippi and Alabama nurseries and pathogenicity of three new species. Phytopathology 105:(in press) 5. Gallegly, M. E., Hong, C. X., Richardson, P. A., and Kong, P. 2010. Phytophthora pini, a valid distinct species. Phytopathology 100:S207 6. Hao, W., and Hong, C. X. 2010. Effect of temperature on survival of chlamydospores and oospores of Phytophthora species in irrigation water. Phytopathology 100:S47 7. Hao, W., and Hong, C. X. 2013. Biological control of Phytophthora nicotianae by heat- tolerant bacteria in irrigation water. Phytopathology 103:S2.56 8. Hao, W., Vinatzer, B. A., and Hong, C. X. 2011. Effect of temperature on survival of Phytophthora and bacterial species in irrigation water. Phytopathology 101:S69

9. Hong, C. X. 2013. Diversity and significance of waterborne pathogens to plant biosecurity under a changing climate. Chinese Journal of Plant Pathology 43:S163 (International Congress of Plant Pathology, Beijing, China, August 25-31, 2013) 10. Hong, C. X., and Richardson, P. A. 2012. Validation of water quality fluctuation patterns in runoff water containment basins of eastern and central Virginia. Phytopathology 102:S4.55 11. Hong, C. X., Richardson, P. A., Ghimire, S. R., Hao, W., Kong, P., Moorman, G. W., Lea-Cox, J. L., and Ross, D. S. 2010. Two new homothallic species of Phytophthora from irrigation reservoirs and natural waterways in Virginia. Phytopathology 100:S51 12. Hong, C. X., Richardson, P. A., Ghimire, S. R., Kong, P., Hu, J. H., Moorman, G. W., Lea-Cox, J. D., and Ross, D. S. 2011. Diversity of Phytophthora species identified in a nursery irrigation runoff water containment basin of eastern Virginia. Phytopathology 101:S74 13. Hong, C. X., Richardson, Kong, P., Edgerton, T., Asaro, C., and Oak, S. W. 2011. Phytophthora species identified from streams in Virginia. Phytopathology 101:S74 14. Kong, P., and Hong, C. X. 2013. Aquatic ecology of pythiaceous plant pathogens. Chinese Journal of Plant Pathology 43:S520 (International Congress of Plant Pathology, Beijing, China, August 25-31, 2013) 15. Kong, P., and Hong, C. X. 2014. Effects of water quality on survival of zoosporic oomycetes and implications. HortScience 49(9):S195 16. Kong, P., Lea-Cox, J. D., Moorman, G. W., and Hong, C. X. 2011. Survival of three quarantine pathogens in a simulated aquatic system at different levels of pH. Phytopathology 101:S93 17. Lanze, C., and Moorman, G. W. 2014. Characterization of Pythium spp. frequently found in recycled irrigation water. Phytopathology 104:S3.66 18. Lea-Cox, J. D., and Belayneh, B. E. 2012. Environmental sensors for measuring weather and intra-canopy conditions In Symposium: The Use, Application and Analysis of Experimental and Field Sensor Data for Horticultural Applications. 109th Annual American Society for Horticultural Science Conference. Miami, FL. HortScience 47(9): S80 19. Lea-Cox, J. D., Belayneh, B. E., and Ristvey, A. G. 2013. Daily and seasonal changes in the water quality of irrigation containment ponds. American Society for Horticultural Science Annual Conference: The Challenges of Using Alternative and Recycled Water Sources for Horticultural Use – Workshop. HortScience 48:S106 20. Ristvey, A. G., Belayneh, B. E., Zazanis, J. P., Beaulieu, J., Balci, Y., and Lea-Cox, J. D. 2014. Investigating alternative pathogen management through sensor-driven irrigation. 111th Annual American Society for Horticultural Science Conference. Orlando, FL. HortScience 49(9): S226-227 21. Yang, X., Brazee, N. J., Loyd, A., and Hong, C. X. 2015. Phytophthora intercalaris, a novel species from streams and irrigation water in eastern United States. Phytopathology 105(in press) 22. Yang, X., Copes, W. E., and Hong, C. X. 2013. Three novel Phytophthora species from irrigation water in Mississippi. Phytopathology 103:S2.164 23. Yang, X., and Hong, C. X. 2012. Isolation of Phytophthora and Pythium species from different depths of sediments in a runoff water sedimentation pond of eastern Virginia. Phytopathology 102:S4.140 24. Yang, X., Tyler, B. M., and Hong, C. X. 2014. Constructing a new phylogeny for the genus Phytophthora. Phytopathology 104:S3.133

Invited Lectures and Contributions to Professional Meetings

Invited lectures and presentations 1. Boyle, K., Hartter, D., Pease, J., Bosch, D., and Xu, W. B. 2014. Consumer preferences for ornamental plants grown with water conservation practices. Annual Meeting of Agricultural and Applied Economics Association, Minneapolis, MN 2. Hong, C. X. 2010. Water recycling and its implications for crop health management. Symposium of Water Issues in the Production of Ornamental Crops in the United States. Land Grant and Sea Grant National Water Conference, Hilton Head, SC 3. Hong, C. X. 2010. Fishing for Phytophthoras – a journey of surprises, Plant Physiology Seminar Series. Virginia Tech (Department of Plant Pathology, Physiology and Weed Science), Blacksburg, VA 4. Hong, C. X. 2010. Fishing for Phytophthoras – a journey of surprises, Zhejiang University, Hangzhou, China 5. Hong, C. X. 2010. Ecology of Phytophthora species in ornamental irrigation water. 17th Ornamental Workshop – Diseases and Insects, Hendersonville, NC 6. Hong, C. X. 2011. Commodity health and quality: advancing postharvest science and technology in a changing world. USDA ARS San Joaquin Valley Agricultural Sciences Center, Parlier, CA 7. Hong, C. X. 2011. Irrigation pathogen mitigation without water treatment. 36th Annual Conference of the International Plant Propagators Society - Southern Region of North America, Valdosta, GA, October 23 to 26, 2011 8. Hong, C. X. 2012. Water dispersal of plant pathogens in a thirsty world. University of Hertfordshire, Hatfield, UK, April 27, 2012 9. Hong, C. X. 2012. Challenges and opportunities for integrated pest management, University of California, Davis, CA, September 24, 2012 10. Hong, C. X. 2012. Fungicide resistance in Phytophthora species attacking ornamentals. 18th Ornamental Workshop – Diseases and Insects, Hendersonville, NC, September 24 to 28, 2012 11. Hong, C. X. 2013. Plant health management in a thirsty world. Christopher Newport University, Newport News, VA, February 22, 2013 12. Hong, C. X. 2013. Treasure hunt in agricultural runoff water containment basins. American Phytopathological Society Potomac Division Annual Meeting/Recent Advancements in Biological Control symposium. Shepherdstown, WV, April 4, 2013 13. Hong, C. X. 2013. Recycled water quality dynamics and implications for ornamental horticultural crop production and health. Virginia Tech (Department of Horticulture), Blacksburg, VA, May 6, 2013 14. Hong, C. X. 2013. Water dispersal of plant pathogens. Cornell University (Department of Plant Pathology and Plant-Microbe Biology), Ithaca, NY, June 26, 2013 15. Hong, C. X. 2013. Recycling irrigation system, a focal point of agricultural water security and plant biosecurity in the 21st century. The First Emerging Information Technology Association (EITA) Conference on Agricultural Sciences and Engineering, Biosystems Engineering (the theme of Precision Agriculture – Challenges and Future Directions), Ithaca, NY, June 27, 2013 16. Hong, C. X. 2015. Specialty crop science and technology in the 21st century. Office of National Programs, USDA Agricultural Research Service, Beltsville, MD, May 22, 2015

17. Hong, C. X. 2015. Integrated pest management in the 21st century. University of California, Davis, CA, July 21, 2015 18. Kong, P., Richardson, P. A., Yang, X., Zhang, H. B., Ghimire, S. R., Copes, W. E., Moorman, G. W., Lea-Cox, J. D., and Hong, C. X. 2014. Biology of Phytophthora species in aquatic ecosystems. The 7th IUFRO Working Party 7.02.09 on Phytophthora in Forests and Natural Ecosystems. Esquel, Chubut, Argentina, November 10 to 14, 2014 19. Kong, P., Richardson, P. A., Yang, X, Zhang, H. B., Ghimire, S. R., Moorman, G. W., Lea-Cox, J. D., Copes, W. E., Ross, D. R., Ristvey, A. G., Boyle, K. J., Bosch, D., Pease, J., and Hong, C. X. 2015. Building crop health into water recycling systems. The 18th International Plant Protection Congress, Berlin, Germany, August 24 to 27, 2015 20. Lea-Cox, J. D. 2012. Some observations on interdisciplinary project planning and management. In: Collaborative Research Projects Highlight the Economic Benefits of Agricultural Research. Webinar organized by the Tri-Societies (ASA/CSSA/SSSA) and Council on Food, Agriculture and Resource Economics (C-FARE) for USDA-NIFA Program Leaders. Washington, DC, October 15, 2012. 21. Lea-Cox, J. D. 2012. Pathogen risk mitigation with good system design and best management practices. 7th International IPM Symposium, Memphis, TN. March 27 to 29, 2012. http://www.ipmcenters.org/ipmsymposium12/27-2_LeaCox.pdf 22. Moorman, G. W. 2011. Oomycetes in irrigation water: Challenges and opportunities. Northeastern Division-American Phytopathological Society annual meeting symposium. New Brunswick, NJ, October 13, 2011 23. Moorman, G. W. 2012. Plant pathogens in irrigation water. 7th International IPM Symposium. Memphis, TN, March 27, 2012 24. Yang, X., Copes, W. E., and Hong, C. X. 2014. Phytophthora species found in irrigation systems and their risk assessments. The 19th Ornamental Workshop on Diseases and Insects, Hendersonville, NC, September 29 to October 3, 2014 25. Yang, X., Tyler, B. M., and Hong, C. X. 2014. A multi-locus phylogeny for the genus Phytophthora. The 7th IUFRO Working Party 7.02.09 on Phytophthora in Forests and Natural Ecosystems. Esquel, Chubut, Patagonia Argentina, November 10 to 14, 2014 Contributed professional society presentations 1. Cultice, A., Bosch, D., Pease, J., and Boyle, K. 2013. Horticultural producers' willingness to adopt water recirculation technology. Agricultural and Applied Economics Association and Canadian Agricultural Economics Society Joint Annual Meeting, Washington, DC, August 4 to 6, 2013 2. Ferraro, N., Bosch, B., and Pease, J. 2015. Economic analysis of recapturing and recycling irrigation on container horticultural nurseries. Southern Nursery Growers’ Association. Atlanta, Georgia, July 21, 2015 3. Hong, C. X., and Moorman, G. W. 2013. Diversity and significance of plant pathogens as agricultural water contaminants. 2013 AWRA Spring Specialty Conference on Agricultural Hydrology and Water Quality II, St. Louis, MO, March 25 to 27, 2013 4. Hong, C. X., Richardson, P. A., Kong, P., and Cafà, G. 2013. Tracking water quality dynamics in a multi-basin agricultural water recycling system, 2013 AWRA Spring Specialty Conference on Agricultural Hydrology and Water Quality II, St. Louis, MO, March 25 to 27, 2013 5. Hong, C. X., Richardson, P. A., Kong, P., Cafà, G., Lea-Cox, J. D., Belayneh, B. E., and Ristvey, A. G. 2013. Dramatic fluctuations of water quality in agricultural runoff

containment basins. 2013 AWRA Spring Specialty Conference on Agricultural Hydrology and Water Quality II, St. Louis, MO, March 25 to 27, 2013 6. Kong, P., and Hong, C. X. 2015. Genetic diversity and abundance of cyanobacteria and associated microbial communities in agricultural runoff containment reservoirs. Phytobiomes 2015: Designing a New Paradigm for Crop Improvement, Washington, DC, June 29 to July 2, 2015 7. Kong, P., and Hong, C. X. 2015. Zoospore exudates suppress plant defense gene expression in Arabidopsis thaliana. The 18th International Plant Protection Congress, Berlin, Germany, August 24 to 27, 2015 8. Yang, X., and Hong, C. X. 2015. Comparative analysis of oomycete diversity between water and sediment in a runoff water sedimentation reservoir in Virginia. Phytobiomes 2015: Designing a New Paradigm for Crop Improvement, Washington, DC, June 29 to July 2, 2015

Outreach Website

1. Irrigation pathogens and water quality at www.irrigation-pathogens.info or http://www.irrigation-pathogens.ppws.vt.edu/. This site was first released to the public in 2011 and updated regularly.

Survey Instruments

1. Hartter, D., Bosch, D., Boyle, K., and Pease, J. 2012. Understanding consumers’ ornamental plant preferences for disease-free and water conservation labels. Online survey of 14,175 ornamental nursery product consumers in Maryland, Pennsylvania, and Virginia, administered in April 2012 2. Cultice, A., Bosch, D., Pease, J., and Boyle, K. 2013. Ornamental nursery survey of irrigation practices and disease management. Survey of 2,035 horticultural growers in Maryland, Pennsylvania, and Virginia administered in February to March 2013

Protocols

Factsheets 1. Copes, W. E., Yang, X., and Hong, C. X. 2015. Well water can be free of Phytophthora species. SCRI Project Factsheet – Pathogen Mitigation Series #5. Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 2. Kong, P., Zhang, H. B., and Hong, C. X. 2015. Water pH dynamics and implications for pathogen management in recycling irrigation ponds. SCRI Project Factsheet – Pathogen Mitigation Series #2. Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 3. Kong, P., Zhang, H. B., and Hong, C. X. 2015. Dissolved oxygen dynamics and implications for pathogen management in recycling irrigation ponds. SCRI Project Factsheet – Pathogen Mitigation Series #3. Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org

4. Kong, P., Zhang, H. B., and Hong, C. X. 2015. Electrical conductivity dynamics and implications for pathogen management in recycled irrigation water. SCRI Project Factsheet – Pathogen Mitigation Series #4. Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 5. Moorman, G. W., and Lanze, C. E. 2015. Diversity and risk of Pythium and Phytopythium species in greenhouse ebb and flood irrigation water. SCRI Project Factsheet – Pathogen Mitigation Series #6. Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 6. Yang, X., and Hong, C. X. 2015. Diversity, risk and management of phytophthora species in irrigation water for ornamental crops. SCRI Project Factsheet – Pathogen Mitigation Series #1. Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 7. Zhang, H. B., and Hong, C. X. 2015. Thermal stratification in recycling irrigation ponds. SCRI Project Factsheet – Recycled Water Quality Series #1. Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 8. Zhang, H. B., and Hong, C. X. 2015. Water pH in recycling irrigation ponds. SCRI Project Factsheet – Recycled Water Quality Series #2. Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 9. Zhang, H. B., and Hong, C. X. 2015. Dissolved oxygen in recycling irrigation ponds. SCRI Project Factsheet – Recycled Water Quality Series #3. Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org Best management practices (BMPs) 1. D’Alessio, N., Boyle, K., Bosch, D., Hartter, D., and Pease, J. 2015. Adding value to ornamental plants. American Nurseryman 215:1 2. Hong, C. X. 2013. SCRI Project Update Series I – Recycled Water Quality: Recycled water quality and management implications. Virginia Nursery and Landscape Association (VNLA) Newsletter 83(3):55-56 3. Hong, C. X. 2013. SCRI Project Update Series I – Water pH dictates chlorine performance. VNLA Newsletter 83 (4):58-60 4. Hong, C. X. 2013. Phytosanitary irrigation webinar series kicked off in October. VNLA Newsletter 83(4):43-44 5. Hong, C. X. 2014. SCRI Project Update Series I – Recycled Water Quality: Three reasons to irrigate crops in the early morning. VNLA Newsletter 84 (1):66-68 6. Hong, C. X. 2014. Water reuse and recycle. Feature Article on the July 2014 issue of Nursery Management (page 56) 7. Hong, C. X. 2015. Keep it clean – new research provides an improved protocol for chlorine water treatment practices. The March 2015 issue of Nursery Management (page 22-24) 8. Moorman, G. W. 2014. BMPs for greenhouse water management. Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org

9. Rees, G., Cultice, A., Pease, J., Bosch, D., and Boyle, K. 2015. Irrigation systems and practices in Mid-Atlantic nurseries. American Nurseryman 215:2 10. Rees, G., Cultice, A., Pease, J., Bosch, D., and Boyle, K. 2015. Disease management issues and practices in Mid-Atlantic nurseries. American Nurseryman 215:3 11. Yang, X., Richardson, P. A., Kong, P., Olson, H. A., and Hong, C. X. 2013. New pathogens causing root and stem rot of Begonia. VNLA Newsletter 83(2):46-48 Web-based learning modules (arranged by module No.) 1. Moorman, G. W. 2015. What plant pathogens could be in my water? Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 2. Moorman, G. W. 2015. How do plant pathogens enter irrigation systems and move around? Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 3. Moorman, G. W. 2015. How can I determine whether my water is clean or contaminated? Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 4. Hong, C. X. 2015. Where should I build my new production facility for crop health? Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 5. Hong, C. X. 2015. How may layout of a recycling irrigation system affect pathogen risk? Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.exetnsion.org 6. Lea-Cox, J. D. 2015. How should I manage irrigation and surface water for pathogen risk mitigation? Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 7. Ristvey, A. 2015. Why is substrate management vital for pathogen risk mitigation? Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 8. Hong, X. C. 2015. How to make the most out of my chlorination dollars? Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 9. Moorman, G. W. 2015. What are current water treatments for greenhouse production? Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 10. Copes, W. E. 2015. Is chlorine dioxide a viable alternative disinfectant for chlorine gas? Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 11. Hong, C. X. 2015. How may water quality in containment ponds change and what does it mean to my crops? Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org 12. Hong, C. X. 2015. What are my options in managing irrigation water pH? Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org

13. Pease, J. 2015. What are my economic perspectives of capturing and reuse of runoff water for irrigation? Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture under eXtension environment at www.extension.org

Webinars

(The first 14 sessions were presented in a series and they are listed by the order by which they were presented)

1. Moorman, G. W., Copes, W. E., Lea-Cox, J. D., Pease, J., Ristvey, A., and Hong, C. X. 2013. A path to plant biosecurity, water and environmental sustainability – SCRI Project overview. Held on October 8, 2013 and recording posted at http://www.irrigation- pathogens.ppws.vt.edu/webinar/october-2013.php 2. Pease, J. 2013. Disease management and irrigation practices of Mid-Atlantic ornamental nurseries. Held on November 6, 2013 and recording posted at http://www.irrigation- pathogens.ppws.vt.edu/webinar/november-2013.php 3. Moorman, G. W. 2014. What plant pathogens could be in irrigation water? Held on December 3, 2013 and recording posted at http://www.irrigation- pathogens.ppws.vt.edu/webinar/december-2013.php 4. Moorman, G. W. 2014. How do plant pathogens get into and move in irrigation water? Held on January 7, 2014 and recording posted at http://www.irrigation- pathogens.ppws.vt.edu/webinar/january-2014.php 5. Moorman, G. W. 2014. How do we determine irrigation water is clean or contaminated? Held on February 4, 2014 and recording posted at http://www.irrigation- pathogens.ppws.vt.edu/webinar/february-2014.php 6. Hong, C. X., Daughtrey, B., and Lancaster, J. 2014. Chlorination of recycled water in ornamental horticultural production. Held on March 4, 2014 and recording posted at http://www.irrigation-pathogens.ppws.vt.edu/webinar/march-2014.php 7. Copes, W. E. 2014. Alternative disinfectant treatments. Held on April 8, 2014 and recording posted at http://www.irrigation-pathogens.ppws.vt.edu/webinar/april-2014.php 8. Ristvey, A. 2014. Substrate management practices vital for pathogen risk mitigation. Held on May 6, 2014 and recording posted at http://www.irrigation- pathogens.ppws.vt.edu/webinar/may-2014.php 9. Lea-Cox, J. D. 2014. Pathogen recycling risk mitigation through system design and best management practices. Held on June 3, 2014 and recording posted at http://www.irrigation-pathogens.ppws.vt.edu/webinar/june-2014.php 10. Hong, C. X. 2014. Locating a new production facility for crop health and sustainability. Held on July 1, 2014 and recording posted at http://www.irrigation- pathogens.ppws.vt.edu/webinar/july-2014.php 11. Hong, C. X. 2014. Building pathogen risk mitigation into water recycling systems. Held on August 5, 2014 and recording posted at http://www.irrigation- pathogens.ppws.vt.edu/webinar/august-2014.php 12. Hong, C. X. 2014. Recycled water quality dynamics and implications for crop health and production. Held on September 2, 2014 and recording posted at http://www.irrigation-pathogens.ppws.vt.edu/webinar/september-2014.php

13. Hong, C. X. 2014. Water pH management for improved horticultural productivity and profit margin. Held on October 7, 2014 and recording posted at http://www.irrigation- pathogens.ppws.vt.edu/webinar/october-2014.php 14. Pease, J., Hartter, D., Boyle, K., Bosch, D., D’Alessio. 2014. Understanding consumer preferences for ornamental plants with disease-free and water conservation labels. Held on November 4, 2014 and recording posted at http://www.irrigation- pathogens.ppws.vt.edu/webinar/november-2014.php 15. Moorman, G. W. 2015. Pythium handling and identification. Webinar presented from Penn State. Held on April 8, 2015 and recording posted at https://meeting.psu.edu/p92gucukw8e/ Text materials include: Module 1: What is Pythium? at http://plantpath.psu.edu/pythium/module-1 Module 2: Pythium isolation and handling protocols at http://plantpath.psu.edu/pythium/module-2 Module 3: Pythium identification; http://plantpath.psu.edu/pythium/module-3 16. Ristvey, A. G., Belayneh, B., Zazanis, J. P., Beaulieu, J., Balci, Y., and Lea-Cox, J. D. 2014. Investigating alternative pathogen management through sensor-driven irrigation. https://ashs.confex.com/ashs/2014/videogateway.cgi/id/814?recordingid=814

Extension and Outreach Presentations

1. Copes, W. E., Yang, X., and Hong, C. X. 2015. Diversity and population dynamics of Phytophthora species in recycling irrigation systems and implications for crop health risk mitigation – Alabama and Mississippi. Mississippi State University Ornamental Horticulture Field Day, Poplarville, MS 2. Copes, W. E., Yang, X., and Hong, C. X. 2015. Diversity and population dynamics of Phytophthora species in recycling irrigation systems and implications for crop health risk mitigation – Alabama and Mississippi. The International Plant Propagators’ Society, Poplarville, MS 3. Copes, W. E. 2016. Managing Phytophthora in recycling irrigation reservoirs. Gulf States Horticultural Expo Trade Show, Mobile, AL 4. Copes, W. E. 2016. Use of chlorine dioxide to disinfect recycled irrigation water. Pacific Agriculture Show, Abbotsford, British Columbia, Canada 5. Hong, C. X. 2013. Making the most out of the agricultural chemical dollars. Eastern Shore Agricultural Conference, Belle Haven, VA, January 4, 2013 6. Hong, C. X. 2013. Getting down to the basics with Phytophthora. Beech Summit, Longwood Garden, Kennett Square, PA. April 5, 2013 7. Hong, C. X. 2013. Water treatment updates. VNLA Field Day, Gloucester, VA, August 8, 2013 8. Hong, C. X. 2013. Recycled water quality dynamics and implications for crop health. Water Management for Ornamental Crops Workshop. Virginia Beach, VA, October 29, 2013 9. Kong, P., Cafa, G., Hao, W., Yang, X., Ghimire, S., Richardson, P. A., and Hong, C. X. 2013. Irrigation systems for crop health, water security and environmental sustainability. VNLA Field Day, Gloucester, VA, August 8, 2013

10. Kong, P., Richardson, P. A., Yang, X, Zhang, H. B., Ghimire, S. R., Copes, W. E., Moorman, G. W., Lea-Cox, J. D., and Hong, C. X. 2014. Biology of Phytophthora species in aquatic ecosystems. Presentations to the external reviewers of Virginia Tech’s Hampton Roads AREC 11. Lea-Cox, J. D. 2011. What is the big picture with water and its availability? How can you cope with the future water needs? 2011 Pest Management Conference. Carroll community College, Westminster, MD, December 1, 2011 12. Lea-Cox, J. D. 2012. Today's water management - issues and updates. Chesapeake Green Conference. Maritime Institute, Baltimore MD, February 10, 2012 13. Lea-Cox, J. D. 2014. The economic impact of better water management decisions. Chesapeake Green Conference. Maritime Institute, Baltimore MD, February 27, 2014 14. Moorman, G. W. 2011. Harbors of plant pathogens in greenhouses. Flowers Canada Conference. Niagara Falls, Ontario, September 4, 2011 15. Moorman, G. W. 2011. Disease diagnosis workshop. Flowers Canada Conference. Niagara Falls, Ontario, September 4, 2011 16. Moorman, G. W. 2012. Root rots and their management. Central Susquehanna Vegetable and Greenhouse Meeting. Mifflinburg, PA, January 24, 2012 17. Moorman, G. W. 2012. Plant pathogens in irrigation water. Western Pennsylvania Spring Greenhouse Night-Lighter. North Belle Vernon, PA, March 22, 2012 18. Moorman, G. W. 2013. Plant pathogens in irrigation water. Northwestern Pennsylvania Greenhouse Seminar. Erie, PA. February 21, 2013 19. Moorman, G. W. 2015. Pythium biology and management. Southeast Pennsylvania Growers Day. East Earl, PA, January 22, 2015 20. Moorman, G. W. 2015. Sanitation for disease control in greenhouses. Mid-Atlantic Fruit & Vegetable Conference. Hershey, PA, January 28, 2015 21. Ristvey, A. G., Belayneh, B., Zazanis, J., Beaulieu, J., Balci, Y., and Lea-Cox, J. D. 2014. Investigating Alternative Pathogen Management through Sensor-driven Irrigation. Chesapeake Green Conference. Sponsored by the Maryland Greenhouse Growers Association. Maritime Institute, Linthicum, MD, February 2014 22. Ristvey, A. G., Belayneh, B., Zazanis, J., Swett, C., and Lea-Cox, J. D. 2015. Investigating alternative pathogen management through sensor-driven irrigation: Part II. Chesapeake Green Conference. Sponsored by the Maryland Greenhouse Growers Association. Maritime Institute, Linthicum, MD, February 2015 23. Zhang, H. B., Richardson, P. A., Belayneh, B. E., Ristvey, A., Lea-Cox, J. D., Copes, W. E., Moorman, G. W., and Hong, C. X. 2014. Recycling irrigation reservoirs: thermal stratification and water quality variation. Presentations to the external reviewers of Virginia Tech’s Hampton Roads AREC

Symposia Organized and Moderated

1. Hong, C. X., and Moorman, G. W. 2012. Integrated management of plant pathogens in thirsty world. 7th International IPM Symposium, Memphis, TN, March 27 to 29, 2012 2. Hong, C. X., and Wohanka, W. 2015. Plant Diseases and Irrigation. The 18th International Plant Protection Congress, Berlin, Germany, August 24 to 27, 2015

Physical Collections

1. Numerous isolates of Pythium from the continuous baiting of recycling irrigation systems in two commercial greenhouses in Pennsylvania were accumulated and some are part of a working collection of over 100 isolates from this research. DNA from each isolate was extracted and is stored at -20C as part of this collection in the Moorman Lab at the Pennsylvania State University. 2. A Pythium and Phytopythium collection of over 200 isolates and their extracted DNA was accumulated. This material was sent to Dr. Carla Garzón, Oklahoma State University, for use in her ongoing Pythium work. 3. DNA sequences for two gene regions (ITS and cox I & II) characteristic of four new Pythium species were submitted to the National Center for Biotechnology Information (GenBank). 4. Cultures of Pythium species discovered and characterized in this work were deposited with Centraalbureau vor Schimmelcultures (Netherlands) for use by scientists. CBS accession nos. 140047, 140048, 140049, 140050, 140051, 140052. 5. Many isolates of Phytophthora, including the type cultures of eleven new species and taxon along with over 2000 bacterial strains, from surveys of recycling irrigation reservoirs in Virginia and Mississippi are part of a working collection maintained in the Hong Lab at Virginia Tech. Type of all new species described in this species were deposited to the Massey Herbarium at Virginia Tech in Blacksburg, VA. Ex-type and additional authentic cultures were deposited at the American Type Culture Collections (ATCC) in Manassas, VA and Centraalbureau voor Schimmelcultures (CBS) in Utrecht, the Netherlands. They also have been supplied to many colleagues here and overseas upon request to support their research and extension programs. 6. More than 2000 DNA sequences of Phytophthora species and bacteria have been deposited at the Genbank for public access. 7. Water quality data are archived at VTechWorks at Virginia Tech for public access.

Major Goals of the Project

This project addresses two critical issues facing the nation's $17 billion green industry (www.nass.usda.gov) through the integration of systems-based, interdisciplinary research and extension activities. It seeks to boost adoption of water recycling irrigation systems, build sustainable plant health beginning during production and extending to garden centers and to the ultimate consumer, and to increase consumer confidence in the quality of plants they purchase. Our ultimate goals are to move the green industry towards greater sustainability and enable nurseries and greenhouses to better compete in global markets while protecting the environment and meeting consumer demands for high quality, healthy plants. The specific objectives are: (1) Characterize species and taxa of Phytophthora and Pythium found in irrigation systems and assess their potential risk to the health of ornamental crops. (2) Develop a better understanding of the dynamics of water quality parameters in reservoirs and develop guidelines to assist irrigation managers in mitigating the risk of nutrient deficiency and toxicity. (3) Significantly increase the understanding of the biology of zoosporic plant pathogens and apply the knowledge to develop best management practice (BMP) protocols for mitigating the dissemination of plant pathogens through irrigation systems. (4) Identify and enhance the buildup of naturally-occurring beneficial microbes in irrigation reservoirs that inhibit zoosporic pathogens. (5) Integrate the BMPs for waterborne pathogen suppression and improved irrigation water quality into current crop

systems. (6) Evaluate the effects that the adoption of BMPs have on production costs, revenue enhancement, and associated social and environmental benefits. (7) Develop an online knowledge center on waterborne pathogens and irrigation water quality management, and use the website to deliver information and educational programs to growers, students and other scientists in order to quickly disseminate science-based knowledge and encourage the adoption of the BMPs developed through this project. This project will generate a wealth of new knowledge and several novel technologies that will have immediate and long-term impacts on the green industry.

What Was Accomplished under These Goals?

This project has greatly advanced the science and technology in a wide range of disciplines from pathogen aquatic biology to applied microbial ecology, hydrology, and socio-economics of recycling irrigation water. These advancements support the hypothesis that pathogen risk associated with recycling irrigation can be mitigated by increasing runoff water turnover time. They have already enabled early adopters to build pathogen mitigation features into water recycling systems and implement best irrigation practices for improved horticultural profitability and sustainability while reducing their environmental footprint. The advancement in pathogen aquatic biology is highlighted by three major discoveries. First, eleven new taxa of Phytophthora were identified, characterized and described from recycling irrigation reservoirs (RIRs) in VA, MS, and MD, with only P. hydropathica having been found to attack ornamental crops so far. Second, great diversity of Phytophthora, Pythium, and Phytopythium species are present in individual RIRs or water tanks with the majority being not aggressive plant pathogens. This discovery highlights the importance of identifying these cultures to species level when determining whether an irrigation water sample is contaminated. Third, the majority of the major Phytophthora and Pythium pathogens are not well adapted to agricultural water environments as perceived over the past 70 years. As demonstrated in the lab assays, their zoospores, the principal infective and dispersal propagules via water are short-lived, in particular under stressful water pH, dissolved oxygen and carbon dioxide environments. An additional product in this line of research is a comprehensive phylogeny for the genus Phytophthora constructed mostly on the sequences of type and authentic cultures. This new phylogeny along with the description of the eleven new species has spurred discoveries of the same species in other regions and countries. They also have reduced and will continue to reduce misidentifications of high-impact species such as P. ramorum in the years to come. Studies of applied microbial ecology have uncovered a distinct bacterial community in RIRs in comparison with natural freshwater lakes and rivers. These studies also have yielded in thousands of bacterial cultures. Few of these individuals alone have been found to effectively affect diseases caused by Phytophthora nicotianae, Pythium aphanidermatum, Py. irregulare, or Py. cryptoirregulare, destructive pathogens of numerous ornamental plants. How they may act together on disease development in the real world is not known at this point. Nevertheless, these resultant bacterial cultures are a significant bio-resource for future studies and development with some cultures already showing biological control activities against the boxwood blight pathogen, an emerging invasive species of national significance. Similarly, tremendous algal diversity was identified from the same reservoirs and their interactions with Phytophthora species is yet to be elucidated. Continuous monitoring of water quality in a dozen RIRs across the Mid-Atlantic and Gulf Coast regions has confirmed that dramatic seasonal and diurnal water quality fluctuation is

common in this emerging aquatic system of global significance. Such fluctuations are stressful for pathogens in the system, thus, pathogen decline along water path from runoff entrance to outlet/pump inlet should be expected. These monitoring data also provided a framework for assessing the recycled water quality impact on performance of agricultural chemicals including chlorine and pesticides that are pH sensitive. The ideal pH for most pesticides is 5 to 6, and pesticides degrade with increasing pH through a hydrolysis process, which can be rapid in the pH range of 8 and 9. Pest control could be greatly diminished or lost completely at the basic pH observed in water from RIRs. Checking pH and acidifying as needed before recycled water is used in a spray solution could easily realize 5 to 20% of the pesticide potential that otherwise would have been lost. In the United States, approximately 500 million kilograms of more than 600 different pesticides are estimated to be applied annually at a direct cost of $10 billion plus an indirect cost of over $10 billion (Pimentel, 2005). This change in practice alone could save $1 to 4 billion per year in the United States. These new data on water quality and the discoveries about pathogen aquatic biology are foundational for recycled water science. It also was discovered for the first time that thermal stratification occurs in relatively small and shallow RIRs; and this stratification contributes to recycled water quality dynamics. However, within individual reservoirs water quality variations are relatively minor. Both consumer and grower surveys have provided important insights into the socio- economics. First, consumers are willing to pay a price premium for horticultural products with disease-free and/or water conservation labels. Second, irrigation water shortages do not stimulate nursery operators to adopt water recycling. Third, adoption of recycling is impeded by fear of increased disease outbreaks. It was estimated that a 6% net cost savings would be required to break even with the increased disease risk of water recycling (=$6,000 for grower with production costs of $100,000). Cost of adopting recycling technology depends on a grower’s location and access to alternative water sources. Analysis of recycling costs revealed that 6 of the 8 case study growers who currently recycle are saving money by recycling compared to obtaining water from wells or municipal systems. Major changes that have been made by early adopters to their existing recycling irrigation system design included: (i) re-routing runoff water flow path on production facilities, (ii) expanding the area and depth of runoff sedimentation reservoirs, (iii) adding new reservoirs to existing water recycling systems, all for the same purposes, extending the runoff water turnover time and settling pathogen out along the water path. The same concept and results also have been used to build pathogen mitigation features into new water recycling systems. Examples of irrigation practice change included (1) placement of the pump inlet immediately below the thermocline of the water column, and (2) irrigating crops in early morning for the best performance of chlorination, a widely-used water treatment that is especially sensitive to alkaline water pH. These changes in system design and practices have put early adopters on track to improved profitability and sustainability. Extending these changes to other production facilities and horticultural crops will have enormous impacts on the nation’s agriculture and consumers by producing more and better quality produces at reduced cost and environmental footprint. This project will continue to promote the horticulture industry’s long-term profitability and sustainability by having educated next generation leaders who will be scientists and educators in water reuse, (ii) built our research and extension capacity and industry partnerships concerned with water use and healthy plant production, and (iii) fostered a broader international network of scientists working on water related plant pathogen issues. A dozen graduate students, seven

postdoctoral associates, and seven summer interns were trained during the past 5 years. Our industry partnership is stronger than ever as evidenced by the total in-kind contributions during the first 4 years ($915,111) already well exceeding that ($752,990) planned for the entire 5-year project period. More importantly, the advisory panel and collaborating growers contributed much to the project quality and productivity by actively taking part in every step from proposal development to research planning, field study execution, data interpretation as well as technology delivery and implementation. A global network on irrigation water availability and quality has been expanded through coordinating the book project, organizing symposia, and participating in other conferences.

What Opportunities for Training and Professional Development Has the Project Provided?

Agricultural and Applied Economics, Virginia Tech

1. Xiang Cao is completing his Ph.D. He is currently finishing a paper analyzing the potential for consumer premiums to compensate growers who produce plants with recycled water. 2. Alyssa Cultice completed her M.S. with project support. Her M.S. thesis addressed producers' willingness to adopt water recirculation technology. 3. Nicole D’Alessio completed her M.S. with project support. Her M.S. thesis addressed market segmentation by consumer environmental preferences. 4. Nathaniel Ferraro completed his M.S. with project support. His M.S. thesis dealt with costs of water recycling on ornamental horticulture operations. 5. David Hartter completed his M.S. with project support including his M.S. thesis on consumer wiliness-to-pay for ornamental plants with disease-free or water conservation labels. 6. Gwen Rees was employed on the project for part of her M.S. program. Her research contributed to publications dealing with horticultural producers’ irrigation and disease management strategies. 7. Weibin Xu was employed on the project for part of his Ph.D. program. His research contributed to publications dealing with consumer willingness-to-pay for ornamental plants with disease-free or water conservation labels.

Hampton Roads AREC, Virginia Tech

1. Lauren Achtemeier, an undergraduate student from Christopher Newport University in Newport News, VA, completed her summer internship in 2011, learning the research process from literature review to project planning, execution, data analysis and interpretation, and writing for publication. Her studies were published along with those of Pistininzi in the Journal of Phytopathology in 2013. 2. Ailing Ben completed her 6-month visiting scholarship on biological control of Phytophthora pathogens. 3. Giovanni Cafa completed his 18-month postdoctoral fellowship project. 4. Nicole Calderone, an undergraduate student from Christopher Newport University in Newport News, VA, completed her summer internship in 2011, learning the research

process from literature review to project planning, execution, data analysis and interpretation, and writing for publication. 5. Venkataramana Chapara, a visiting postdoctoral scientist from University of Illinois, completed a 4-week Oomycete Genomics Fellowship from the National Science Foundation via Oomycete Molecular Genetics Network. 6. Wei Hao earned her Ph.D. and completed an 8-month postdoctoral fellowship. She attended annual meeting of the American Phytopathological Society every year. 7. Kevin Hu, a high school junior from an International Baccalaureate Program at Princess Anne High was trained in microbiology and a statistical analysis package – R (2012 and 2013) 8. Mrina Nikrad attended the Mothur Workshop on microbial diversity in Detroit, MI, March 2014 during her 12-month postdoctoral fellowship working on ammonium- oxidizing archaea and bacterial in recycling irrigation reservoirs. 9. Michael Pistininzi, an undergraduate student from Christopher Newport University in Newport News, VA, completed his summer intern project in three consecutive years of 2011-2013, learning the research process from literature review to project planning, execution, data analysis and interpretation, and writing for publication. He presented his results at the annual project meetings. His studies were published in the Journal of Phytopathology (2013) 10. Andrew Rotzin, an undergraduate student from Christopher Newport University in Newport News, VA, completed his summer internship in 2012, learning the research process from literature review to project planning, execution, data analysis and interpretation, and writing for publication. 11. Xiao Yang earned his Ph.D., followed by a 6-month postdoctoral fellowship. He attended the annual meetings of the American Phytopathological Society and participated in several professional development workshops with Analysis of Population Genetic Data in R and Introduction to Bayesian Analysis in Plant Pathology in Minneapolis, MN (2014) and Ornamental Pathology Tour in Pasadena, CA (2015). In addition, he attended Oomycete Boinformatics Training and Phytophthora parasitica Genome Annotation Jamboree in Blacksburg, VA (2012) and a Mothur workshop on microbial diversity in Detroit, MI (2015). 12. Haibo Zhang participated in the AWRA Annual Water Resources Conference in Tysons Corner, VA (2014) during her 21-month postdoctoral fellowship.

Pennsylvania State University

1. Maria L. Burgos-Garay earned her Ph. D., participated at the Oomycete Molecular Genetics Network meetings and the Fungal Genetics Conference (Asilomar Conference Center in Pacific Grove, CA), and completed an 18-month postdoctoral project. 2. Carla E. Lanze earned her M. S., participated at the Oomycete Molecular Genetics Network meetings and the Fungal Genetics Conference (Asilomar Conference Center in Pacific Grove, CA), participated in the Oomycete Bioinformatics Workshop at Virginia Tech, and trained in genotyping-by-sequencing. 3. Laura del Sol Bautista-Jalón (Ph. D. candidate) trained in genotyping-by-sequencing.

How Have the Results Been Disseminated to Communities of Interest?

Both conventional methods and multimedia were used in the dissemination of project results for the broadest reach to communities of interest. The major instruments used to reach the horticulture industries and the public included an outreach website, project-wide annual meetings and regular web conferences, extension presentations, a 14-session webinar series, trade magazine contributions, and an online knowledge center. Those used to reach researchers, extension educators, and policy makers included one book, book chapters, refereed journal articles, invited lectures and presentations, and international symposia. Specifically, the webinar series was added to the project for expedited delivery to end users. International outreach was accomplished by coordinating and editing one book, organizing two symposia, and presenting project results at international congress and workshops.

Outreach Website: Irrigation Pathogens and Water Quality (http://www.irrigation- pathogens.ppws.vt.edu/index.php)

This website was first established in 2011 and updated regularly to communicate with the green industry and the public on our vision, mission and approaches, and highlight the project activities and major accomplishments. It also served as an effective instrument for announcing and promoting a 14-session webinar series on irrigation pathogens and water quality, and now for permanent housing of the webinar recordings. To help the industry manage boxwood blight, an emerging disease of national significance, a new tab was added to the site with the latest research and extension materials. In addition, this site provides links to other major resources on irrigation water availability and quality issues. According to the Google analytics, this outreach website has been visited by numerous viewers in the US and from over 60 foreign countries.

Annual Project Meetings and Web Conferences

Project-wide meetings were held annually in Virginia Beach, VA, along with regular web conferences, to keep the advisory panel and collaborating growers posted of project progress and solicit their input on project data analysis, interpretation and application. Panel members and collaborating growers are early adopters of new knowledge and technology. Many collaborating growers already have used the pathogen aquatic biology research data to modify their existing water recycling systems. These modifications included: (i) re-routing runoff water flow path, (ii) expanding the area and depth of runoff containment reservoirs, (iii) adding new reservoirs, all for the same purposes, extending the runoff water turnover time and settling pathogens out along the water path. They also used the same concept and results to build pathogen mitigation features into water recycling systems at new production facilities. In addition, they used recycled water quality research data to determine at which depth of the water column to place pump inlet and when to irrigate crops for the best performance of chlorination, a widely-used water treatment that is prone to alkaline water pH degradation. These early adoptions have set and will continue to serve as powerful examples for fellow growers to follow for improved crop health, water and environmental sustainability.

Extension and Outreach Presentations

In addition to communicating with the panel members and collaborating growers, we presented the project results at over twenty extension and outreach venues. These covered a variety of crops from ornamentals to vegetables, fruit, etc. at state (e.g., Chesapeake Green Conference, VNLA Field Days), national (Beach Summit), and international levels (Flowers Canada Conference, International Plant Propagators’ Society Annual meetings).

Webinar Series: Irrigation Pathogens and Water Quality

This 14-session webinar series was added to the project for expedited tech delivery to the end users. It exemplified the partnership between the project team and its collaborating growers and institutions. Growers actively involved in the development and delivery of the webinar materials and participated in the discussion after each presentation. AmericanHort, the Society of American Florists, network of ornamental pathologists and entomologists, and other collaborating institutions helped promote the webinar series and individual sessions through their memberships. These webinars were delivered via Adobe Connect at https://connect.extension.iastate.edu/irrigation-water/. They were well attended with participants from coast to coast and from Canada to Florida. All webinar sessions including discussion were recorded and the recordings are archived at http://www.irrigation- pathogens.ppws.vt.edu/webinar/index.php. Additional webinars were conducted on Pythium and Phytopythium: isolation, handling and culture identification and on pathogen management through sensor-driven irrigation.

One-on-One Consultations with Growers

Numerous consultations were conducted through on-site visit, email exchange and via phone conversation to advise on irrigation pathogens and recycled water quality. Disease diagnoses were completed on samples submitted by growers, retailers, landscapers as well as extension agents concerned about plant pathogens in irrigation water.

Online Knowledge Center: Irrigation Water Management for Ornamental Horticulture (www.extension.org)

An online knowledge center on irrigation water management for ornamental horticulture was recently released to the public. This knowledge center consists of thirteen learning modules, a number of factsheets and best management practices (BMPs) protocols, as well as links to other major online resources on irrigation water availability and quality issues. It also includes an Excel-based assessment tool on its home page for learners to evaluate their production cases and determine which module(s) to begin with. This online knowledge center will serve the horticultural industries well in the years to come.

Scientific Publications

The project results were disseminated to researchers, educators, postdoctoral associates, graduate and undergraduate students, extension specialists and agents, professional consultants via eight theses and dissertations, over forty refereed journal articles, one book, seventeen book chapters, and twenty-four abstracts.

Lectures and Presentations

Research results were also disseminated to the science communities and educators via over 25 invited lectures in institutions here (e.g., Cornell University, Ithaca, NY) and overseas (University of Hertfordshire, Hatfield, UK), and presentations at regional (APS Divisional meetings), national (Land Grant and Sea Grant National Water conference), and international meetings (International Crop Protection Congress) as well as voluntary contributions.

International Symposia

In addition to presenting the project results at professional meetings, two symposia were organized on irrigation pathogen management, in conjunction with the 7th International IPM Symposium in Memphis, TN, March 27 to 29, 2012, and the 18th International Plant Protection Congress in Berlin, Germany, August 24 to 27, 2015, respectively. These symposia not only provided effective outreach platforms for this project but also fostered future collaborations on this issue of growing global significance.

The Book: Biology, Detection and Management of Plant Pathogens in Irrigation Water

This book was a product of collaboration with 49 world leading plant pathologists, horticulturists, and agricultural engineers contributing chapter contents. It consists of 30 chapters in five parts: The chapters in the first four Parts reviewed and summarized the existing literature on irrigation pathogens and those in Part V highlighted the new approaches and latest research data from this project. The book chapters were written for both science communities and growers of different horticultural crops including ornamentals, vegetables, tree fruits and nuts. This comprehensive resource published by the American Phytopathological Society was released in July 2014 and immediately became one of its best sellers of the year. An e-book is currently being prepared by the Society to further extend its reach, applications and impacts.

What Do You Plan to Do during the Next Reporting Period to Accomplish the Goals?

Project completed.

Group photo of participants who physically attended the fifth annual project meeting in the Virginia Tech’ Agricultural Research and Extension Center in Virginia Beach VA during March 12 and 13, 2015 (from left to right): Warren Copes, Darrell Bosch, Gary Moorman, Xiang Cao, Marianne Elliott, Nathaniel Ferraro, Robert Alex, Dewayne Stables, Hank Thornburg, Xiao Yang, James Pease, Joshua Pickett, Matthew Sawyer, Bruk Belayneh, Isaac Brantingham, Douglas Eller, Peter Schultz, Ping Kong, Gary Cooper, Chuanxue Hong, Andrew Ristvey