scri final report
TRANSCRIPT
FINAL REPORT SCRI Project (Agreement #: 2010-51181-21140):
Integrated Management of Zoosporic Pathogens and
Irrigation Water Quality for a Sustainable Green Industry
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
industry partnerships, and built a
broad international network of
scientists working on irrigation
pathogen issues, which all will
continue promoting the green
industry’s long-term sustainability
in the years to come.
i
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)
ii
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
iii
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
1
PRODUCT HIGHLIGHT
2
3
A Comprehensive Resource on Biology, Detection and Management of Plant Pathogens in
Irrigation Water
4
A 14-Session Webinar Series on Irrigation Pathogens and Water Quality
5
An Outreach Website Highlighting the Project Vision, Mission, Approaches, Research/
Educational Programs, and Major Accomplishments
6
An Online Knowledge Center on Irrigation Water Management for Ornamental
Horticulture
7
PRECIOUS MOMENTS
8
9
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
10
11
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
12
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
13
A BRIEF ACCOUNT OF ACTIVITIES AND
ACCOMPLISHMENTS
14
15
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)
16
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)
17
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)
State
Nursery/
Greenhouse
Anticipated
5-year total
Actual total
contributions
by the end of year 4 Balance
Alabama Flowerwood $47,035.00 $55,250.40 $8,215.40
Maryland Homestead/
Tidal Creek
$64,125.00 $73,783.00 $9,658.00
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
18
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
19
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
20
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
21
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
22
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
23
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)
24
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
25
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
26
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
27
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
28
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
29
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
30
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
31
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
32
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
33
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
34
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
35
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
36
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
37
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
38
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.
39
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
40
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.
41
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.
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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
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