Topic outline

  • General

    .

    Welcome to the Online Knowledge Center on Irrigation Water Management for Ornamental Horticulture! 

    Agricultural runoff capture and reuse is essential to securing an adequate supply of water for irrigation and reducing nonpoint source pollution. However, this practice potentially could recycle and spread destructive plant pathogens from isolated infections to entire farms and deteriorate pond water quality, resulting in significant crop losses at production facilities and negatively impacting retailers, landscapers, and consumers. This knowledge center was developed by teams of plant pathologists, horticulturists, economists and information technologists on the USDA National Institute of Food and Agriculture – Specialty Crop Research Initiative project: Integrated management of zoosporic pathogens and irrigation water quality for a sustainable green industry. It presents the up-to-date knowledge and technology as well as the latest research data on irrigation water management for ornamental horticulture. The knowledge center consists of three major sections:

    • Web-based learning modules
    • Best management practices (BMPs) and factsheets
    • Other educational materials, programs, and resources

    There are thirteen learning modules in total with each focusing on a general question.  We have developed self-assessment sheets in Excel format to help learners determine which learning modules to begin with.  You can complete the self-assessment sheets which will then take you to the learning modules that best address your immediate needs.  If you already have clear questions in mind and look for answers to those questions, you are also encouraged to review learning module titles then select the ones that best meet your needs.

    Our goal is to enable farmers to capture and reuse runoff water for irrigation without recycling plant pathogens while improving irrigation water quality.

    Click here to view this recorded webinar on Introduction to the Plant Pathogens in Irrigation: Team and project overview.

    This knowledge center audience:
    •    Growers, retailers
    •    Extension specialists and agents
    •    Irrigation specialists
    •    Crop health professionals
    •    Horticulturists, plant pathologists, mycologists and microbiologists
    •    Undergraduate and graduate students, postdoctoral associates
    •    Conservation biologists
    •    Policy makers

    Participants will learn about diversity, aquatic biology, detection technology and management strategies of plant pathogens in irrigation water. This knowledge center will significantly increase the profitability and sustainability of the green industry, enhance the aesthetic value of recreational parks and landscapes, and improve consumer satisfaction. It also will reduce the risk of unintentional dissemination of quarantine pathogens (e.g., Phytophthora ramorum) through trade of ornamental plant stocks. These benefits can and will extend to other specialty crop industries facing the same crop health and water issues.

     

    • Major Contributors of Content

      Chuan Hong, James Pease (Virginia Tech), Gary Moorman (Pennsylvania State University), John Lea-Cox, Andrew Ristvey (University of Maryland), Warren Copes (USDA-ARS-Southern Horticultural Laboratory)

      Dr. Chuan Hong, Project Director and Professor of Plant Pathology, Virginia Tech, Virginia Beach, VA
      The primary goal of Dr. Hong’s program is to develop science-based sustainable solutions to plant biosecurity, water and environmental sustainability under a changing climate, and enable growers and other clientele to make informed management decisions on these highly interconnected issues of global significance. He also conducts a variety of other extension programs to meet their routine and emerging needs for disease control. He has authored over 100 refereed journal articles, five books and a number of book chapters, plus numerous extension publications.


      Dr. Warren Copes, Project Co-Director and Research Plant Pathologist, USDA-ARS, Thad Cochran Southern Horticulture Laboratory, Poplarville, MS
      The primary goal of Dr. Copes’ research program is to develop integrated cultural and chemical control strategies for disease problems that affect ornamental woody plants produced in commercial nurseries in the Gulf coast region of the U.S. Sanitation is one preventive control approach when applied at key points may impact a pathogen's population severely enough to minimize the risk of severe disease outbreaks. One of his research goals is to evaluate timing and dose of disinfectants in treating irrigation water.


      Dr. John Lea-Cox, Project Co-Director, Professor of Plant Physiology and Nursery Extension Specialist, University of Maryland, College, Park, MD
      The primary goal of his research and extension programs is to increase the efficiency of water and nutrient use in the nursery and greenhouse industries.  In order to achieve these goals, He has led a number of interdisciplinary projects, most recently a $5.2M USDA-SCRI project that has developed advanced sensor-based networks, to provide farmers with real-time information about their own operations. By doing this, He and his teams have not only demonstrated significant reductions in water and nutrient use, but increased the profitability of those operations in many and diverse ways.  More information on the project, participants and impacts can be accessed from http://smart-farms.net/impacts.  During his career, John has co-authored one book and six book chapters, published 28 peer-reviewed journal articles, 32 national and international conference papers, and more than 70 society, trade or extension articles.  Further information can be accessed from http://psla.umd.edu/people/dr-john-lea-cox.


      Dr. Gary Moorman, Project Co-Director and Professor of Plant Pathology, the Pennsylvania State University, University Park, PA
      The primary goals of Dr. Moorman's research are to identify the Pythium species causing crop losses in greenhouses, better understand their biology, and characterize their interactions with non-pathogenic Pythium species and bacteria often found in recycling greenhouse irrigation systems. Another goal is to detect and monitor fungicide resistance in Pythium populations and develop strategies for managing Pythium-caused plant diseases. In addition to this research, Moorman is the Extension plant pathologist at Penn State for woody ornamentals, shade trees, and floricultural crops and teaches the online course, Diseases of Horticultural Crops.

      Dr. James Pease, Project Co-Director and Professor of Agricultural and Applied Economics, Virginia Tech, Blacksburg, VA
      Dr. Pease seeks to provide new research and context-specific information to all growers to make rational tradeoffs between economic and environmental outcomes. In particular, He believes that comprehensive quantitative planning, entrepreneurship, and environmental coconsciousness will provide consumer satisfaction, business success, and a well-functioning ecosystem. His extension programs work closely with local Cooperative Extension and cooperating private business personnel.


      Dr. Andrew Ristvey, Project Co-Director and Associate Professor of Horticulture, University of Maryland, Queenstown, MD
      With a research/extension based program orientated towards potting media/substrate management, Dr. Ristvey is developing studies to answer questions about how cultural management practices such as handling, fertilization and especially irrigation management affect the susceptibility of container-grown plants to diseases like Phytophthora.  Understanding the relationship between plant health and what circumstances affect the degree of pathogenicity and plant pathogen virulence.


      • 1. What plant pathogens could be in my water?

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        By Dr. Gary Moorman (gmoorman@psu.edu)

        Learning objectives

        Members of almost every major group of plant pathogens have been found in water, in particular, fungi, oomycetes, bacteria, viruses, and nematodes. Within each group, there is tremendous variation in life histories; while some are of little consequence when found in irrigation water, others pose a high risk for causing crop losses. Sections of this module deal with each general group.

        In this module, you will...
        • Discover which specific plant pathogens pose a risk of causing crop losses when in irrigation water
        • Develop a better understanding about their life history that allows them to survive and spread via water and infect plants
        • Build a foundation of knowledge that will help you understand the management of these pathogens, information that is presented in other modules

        Learning materials

        Additional reading materials
        • Hong C. X., and Moorman G. W.  2005.  Plant pathogens in irrigation water: challenges and opportunities. Critical Reviews in Plant Sciences 24:189-208
        • Hong, C. X., Moorman, G. W., Wohanka, W. and Büttner, C.  2014.  Biology, Detection and Management of Plant Pathogens in Irrigation Water. APS Press, St. Paul, MN
        • Stewart-Wade SM. 2011.  Plant pathogens in recycled irrigation water in commercial plant nurseries and greenhouses: their detection and management. Irrigation Science 29:267-297
        • Zappia, R. E., Huberli, D., Hardy, G. E. S. J., Bayliss, and K. L. 2014. Fungi and oomycetes in open irrigation systems: knowledge gaps and biosecurity implications. Plant Pathology doi:10.1111/ppa.12223

        • 2. How do plant pathogens enter irrigation systems and move around?

          irrigation

          By Dr. Gary Moorman (gmoorman@psu.edu)

          Learning objectives

          Depending upon the particular plant pathogen of concern, it may be harbored in infected weeds or wild plants in the vicinity of the water supply, in soil, in infected plants in the production area, in debris from a previous crop, or may enter the production areas on wind currents or through insect or human or animal activity. Once in irrigation water, they can be spread in various ways. These topics will be discussed so that you can think about them in terms of your production system.

          In this module, you will…

          • Recognize where the plant pathogens that are spread via water are harbored
          • Discover how plant pathogens get from those refuges into the water
          • Use a worksheet to identify where in your production facility pathogens may be harbored

          Learning materials

          Additional reading materials

          • Hong C. X., and Moorman G. W.  2005.  Plant pathogens in irrigation water: challenges and opportunities. Critical Reviews in Plant Sciences 24:189-208
          • Hong, C. X., Moorman, G. W., Wohanka, W. and Büttner, C.  2014.  Biology, Detection and Management of Plant Pathogens in Irrigation Water. APS Press, St. Paul, MN
          • Stewart-Wade SM. 2011.  Plant pathogens in recycled irrigation water in commercial plant nurseries and greenhouses: their detection and management. Irrigation Science 29:267-297
          • Zappia, R. E., Huberli, D., Hardy, G. E. S. J., Bayliss, and K. L. 2014. Fungi and oomycetes in open irrigation systems: knowledge gaps and biosecurity implications. Plant Pathology doi:10.1111/ppa.12223

          • 3. How can I determine whether my water is clean or contaminated?

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            By Dr. Gary Moorman (gmoorman@psu.edu)


            Learning objectives

            If you suspect that a plant pathogen affecting your crop is coming from your water or if you are treating water that you know contains plant pathogens, then you need have water tested to determine that the water really does or does not contain the pathogen. A brief overview of the methods used on your samples to detect each of the important plant pathogens will be given.  It is important to collect a sample in the manner and location most likely to capture the plant pathogen so that if plant pathogens are not found in the water, it is probably because they are not present and not because they were missed in the sampling.

            After reviewing this module you will be able to…

            • Determine where, when, and how much water needs to be collected in order to determine whether pathogens are present
            • Differentiate what methods are applied to initially determine that plant pathogens are present in the water and what methods must be used to verify that water treatments are being in eliminating them from the water
            • Recognize what information you must receive from a testing lab for it to be useful to you
            • Decide where samples can be sent for plant pathogen testing and what kits are available to you to do your own testing.


            Learning materials



            Additional reading materials

            • Hong C. X., and Moorman G. W.  2005.  Plant pathogens in irrigation water: challenges and opportunities. Critical Reviews in Plant Sciences 24:189-208
            • Hong, C. X., Moorman, G. W., Wohanka, W. and Büttner, C.  2014.  Biology, Detection and Management of Plant Pathogens in Irrigation Water. APS Press, St. Paul, MN
            • Stewart-Wade SM. 2011.  Plant pathogens in recycled irrigation water in commercial plant nurseries and greenhouses: their detection and management. Irrigation Science 29:267-297

            • 4. Where should I build my new production facility for crop health?

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              By Dr. Chuan Hong (chhong2@vt.edu)

              Learning objectives

              Are you thinking to start a new production facility? Do you wish to build crop heath and sustainability into your new facility? Are you interested in learning the expanded concept of disease prevention? If your answer to any of these questions is YES, this learning module is for you!

              After reviewing this learning module, you will be able to:

              • Recognize the pathogen risk associated with major water sources
              • Develop a new concept that where to build a new production facility matters in terms of crop health risk management
              • Locate your new production facilities for long-term crop health and sustainability

              Learning materials

              Additional reading materials

              • Hong, C. X. 2008. Management of Pathogens in Irrigation Water.  Green Industry Knowledge Center for Water and Nutrient Management Learning Modules. J. D. Lea-Cox, D. S. Ross (eds.) http://www.waternut.org/moodle/course/view.php?id=56
              • Hong, C. X.  2011.  Irrigation pathogen mitigation without water treatment. Proceedings of the 36th Annual Conference of the International Plant Propagators Society - Southern Region of North America (Valdosta, GA) at http://ipps-srna.org/pdf/2011Papers/4-%20Hong-Chuan-2011.pdf
              • Hong, C. X.  2014.  Component analysis of irrigation water in plant disease epidemiology.  Page 111-122  In Biology, Detection and Management of Plant Pathogensin Irrigation Water.  C. X. Hong, G. W. Moorman, W. Wohanka, C. Büttner (eds). APS Press. St. Paul, MN
              • Ross, D. R.  2014. Water resources and Recycling irrigation system designs for healthy crops.  Pages 321-332  In Biology, Detection and Management of Plant Pathogens in Irrigation Water.  C. X. Hong, G. W. Moorman, W. Wohanka, C. Büttner (eds). APS Press. St. Paul, MN

              • 5. How may layout of a recycling irrigation system affect pathogen risk?

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                By Dr. Chuan Hong (chhong2@vt.edu)


                Learning objectives

                Plant pathogens in irrigation water were recognized as a significant crop health issue about a century ago and the scope and degree of their impacts have since increased with increasing use of recycled water for irrigation. Does water capture and reuse have to be at the cost of crop health?  Is it possible to capture and reuse agricultural runoff without recycling and spreading plant pathogens from isolated infections to entire farms? These questions will be covered in this module.

                After reviewing this learning module, you will …

                • Recognize how pathogen diversity and populations may change along water path from runoff entrance to outflow point in containment ponds
                • Develop a new concept that waterborne pathogen risk can be mitigated by using better designs of water recycling system
                • Be able to design and implement new water recycling systems and/or modify existing system for long-term pathogen risk mitigation.

                Learning materials

                Additional reading materials

                • Hong, C. X.  2008.  Management of Pathogens in Irrigation Water.  Green Industry Knowledge Center for Water and Nutrient Management Learning Modules. J. D. Lea-Cox, D. S. Ross (eds.) http://www.waternut.org/moodle/course/view.php?id=56
                • Hong, C. X.  2011.  Irrigation pathogen mitigation without water treatment. Proceedings of the 36th Annual Conference of the International Plant Propagators Society - Southern Region of North America (Valdosta, GA) at http://ipps-srna.org/pdf/2011Papers/4-%20Hong-Chuan-2011.pdf
                • Hong, C. X.  2014.  Component analysis of irrigation water in plant disease epidemiology.  Page 111-122  In Biology, Detection and Management of Plant Pathogens in Irrigation Water.  C. X. Hong, G. W. Moorman, W. Wohanka, C. Büttner (eds). APS Press. St. Paul, MN
                • Ross, D. R.  2014. Water resources and Recycling irrigation system designs for healthy crops.  Pages 321-332  In Biology, Detection and Management of Plant Pathogens in Irrigation Water.  C. X. Hong, G. W. Moorman, W. Wohanka, C. Büttner (eds). APS Press. St. Paul, MN

                • 6. How should I manage irrigation and surface water for risk mitigation?

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                  By Dr. John Lea-Cox (jlc@umd.edu)

                  Learning objectives

                  Recycling water in nursery and greenhouse operations is fast becoming a necessity, not only in the Western US but virtually in every state, due to periodic droughts and increasing limitations on the use of freshwater resources.  The use of using recycled water can pose challenges for disease management, if basic water management procedures are not followed.  Our group is focusing on reducing the risks of pathogen movement by increasing the efficiency and precision of irrigation management techniques, by only applying irrigation water when the plant requires it.That is a challenge, without having the tools that can provide us with soil moisture data, both consistently and reliably.  


                  After reviewing this learning module, you will...

                  • Recognize the basic irrigation management principles for pathogen management
                  • Differentiate the sensor network tools that we have developed, which dramatically increase the precision of irrigation water applications,
                  • Develop a better understanding of the impact of reducing irrigation frequency on minimizing leaching and runoff from production areas
                  • Recognize how drier, antagonistic production environments can reduce pathogen survival in the root zone, and inhibit zoospore movement via runoff from production areas into recycling ponds.

                  Learning materials

                  Additional reading materials

                  • 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).  APS Press. St. Paul, MN



                  • 7. Why is substrate management vital for pathogen risk mitigation



                    By Dr. Andrew Ristvey (aristvey@umd.edu)

                    Learning objectives

                    Potting substrates or media come in all forms, each having various characteristics that should be understood and managed accordingly.  Careful management of these substrates is essential for mitigating the risk of pathogens entering and negatively affecting the production system.  Creating cultural conditions that prevent disease development is an important step in disease management, well before the first application of fungicides.  This Knowledge Center module will go over methods of effective substrate management, from initial inspection of media to well after the plants have been dibbled in. This Knowledge Center module will show the learner, not only how, but why these methods are necessary, from discussion of theory to practical implementation of best management practices.

                    After reviewing this module, you will

                    • Recognize the factors of substrate physical properties and monitoring methods
                    • Be familiar with the factors of substrate chemical properties and monitoring methods
                    • Be able to evaluate substrate physical and chemical properties, and
                    • Handle soilless substrate from delivery to potting in ways that promote pathogen risk mitigation.


                    Learning materials

                    Additional reading materials

                    • Handreck, K. and N. Black. 2010. Growing Media for Ornamental Plants and Turf (4th ed.). Univ. New South Wales Press, Sydney, Australia. pp.  551.
                    • Raviv, M., and Lieth, J. H. 2008. Soilless Culture: Theory and Practice. M. Raviv and J. H. Lieth, eds. Elseveir, New York. pp. 608
                    • Ristvey, A. G., and Moorman, G. W.  2014.  An integrated approach to minimizing plant pathogens in runoff water from containerized production systems. Pages 365-376  In Biology, Detection and Management of Plant Pathology in Irrigation Water.  C. X. Hong, G. W. Moorman, W. Wohanka, and C. Büttner (eds).  APS Press. St. Paul, MN

                    • 8. How to make the most out of my chlorination dollars


                      By Dr. Chuan Hong (chhong2@vt.edu)


                      Learning objectives

                      Plant pathogens in irrigation water pose a serious threat to crop health locally and plant biosecurity globally as the horticulture industry increasingly depends upon recycled water for irrigation.  The short-term solution to this emerging crop health issue is to treat recycled water before use for irrigation. Chlorination is the most cost-effective water treatment technology available today.

                      After reviewing the learning module, you will …

                      • Recognize the concentration of free chlorine and contact time required to kill major pathogens in irrigation water
                      • Develop a better understanding of chlorine chemistry and water quality factors affecting its pathogen-killing power
                      • Use the five simple tricks to improve the economics of your chlorination-based water treatment.

                      Learning materials


                      Additional reading materials

                      • Hong, C. X., Richardson, P. A., Kong, P., and Bush, E. A.  2003.  Efficacy of chlorine on multiple species of Phytophthora in irrigation water.  Plant Disease  87:1183-1189
                      • Fisher, P. R.  2014.  Selecting a treatment method for irrigation water.  Pages 289-302  In Biology, Detection and Management of Plant Pathogens in Irrigation Water.  C. X. Hong, G. W. Moorman, W. Wohanka, C. Büttner (eds). APS Press. St. Paul, MN
                      • Fisher, P. R., Huang, J. S., Raudales, R. E., Meador, D. P.  2014.  Chlorine for irrigation water treatment. Pages 235-266  In Biology, Detection and Management of Plant Pathogens in Irrigation Water.  C. X. Hong, G. W. Moorman, W. Wohanka, C. Büttner (eds). APS Press. St. Paul, MN


                      • 9. What are current water treatments for greenhouse production?

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                        By Dr. Gary Moorman (gmoorman@psu.edu)

                        Learning objectives

                        There are many different types of water treatments that could be used to greatly reduce or eliminate the various plant pathogens from irrigation water. An overview will be given of what is necessary to effectively use each treatment as well as what factors make it likely that a particular treatment will be effective. The quality and quantity of the water to be treated are major factors determining what method will work for you.


                        After reviewing this module, you will be able to:

                        • Analyze the pros and cons of each water treatment method
                        • Estimate the cost of installing, maintaining, and operating each different water treatment method
                        • Develop a better understanding of what skills and equipment required to use each water treatment method effectively
                        • Recognize the needs for licenses, certifications, or permits required for using certain water treatment methods
                        • Select the water treatment method that fits best into your operation.


                        Learning materials

                        • 10. Is chlorine dioxide a viable disinfectant for chlorine gas

                          By Dr. Warren Copes (Warren.Copes@ARS.USDA.GOV)

                          Learning objectives

                          Chlorine products are well accepted disinfectants used to inactivate plant pathogen propagules being dispersed in irrigation water, and these products are presented in a previous learning module. The main focus of this module is to present an alternative chlorine product, chlorine dioxide that provides good biocidal activity over broad pH and temperature ranges, and has low reactivity to compounds such as ammonia and certain types of organic matter. Two types of delivery systems will be described.

                          After reviewing this learning module, you will …

                          • Recognize what water properties may dramatically influence use of disinfectants, and how these properties effect chlorine dioxide activity
                          • Develop a better understanding on the pros and cons of chlorine dioxide relative to other chlorine products
                          • Select a method to generate and apply chlorine dioxide that best fit your operation.

                          Learning materials

                          Additional reading materials

                          • Copes, W. E., Barbeau, B., and Chastagner, G. A.  2014.  Chlorine dioxide. Pages 251-265  In: Biology, Detection and Management of Plant Pathogens in Irrigation Water. C. X. Hong, G. Moorman, W. Wohanka, and C. Büttner (eds). APS Press, St. Paul, MN

                          • 11. How may water quality in containment ponds change and what does it mean to my crops?

                            By Dr. Chuan Hong (chhong2@vt.edu)

                            Leaning objectives

                            Agricultural runoff capture and reuse is essential to ensuring an adequate supply of water for irrigation while preventing pollution. But this practice potentially deteriorates pond water quality which could directly affect crop health and production. The module will present the latest research data on water quality in recycling irrigation reservoirs and adjacent stream and discuss their applications.

                            After reviewing this learning module, you will …

                            • Differentiate water quality between containment ponds and natural lakes/streams
                            • Recognize how containment pond water quality may affect crop health and production
                            • Be able to make informed decision on water quality monitoring and management for improved crop health and production.
                            • Develop a better understanding of what drives the water quality dynamics in these ponds

                            Learning materials

                            Additional reading materials

                            • 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
                            • 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
                            • 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
                            • Hong, P., Lea-Cox, J. D., and Hong, C. X.  2012. Effect of electrical conductivity on survival of Phytophthoraalni, P. kernoviae and P. ramorum in a simulated aquatic environment.  Plant Pathology 61:1179-1186
                            • Hong, C. X., Lea-Cox, J. D., Ross, D. S., Moorman, G. W., Richardson, P. A., Ghimire, S. R., and Kong, P.  2009.  Containment basin water quality fluctuation and implications for crop health management. Irrigation Science  27:485-496




                            • 12. What are my options in managing irrigation water pH?

                              By Dr. Chuan Hong (chhong2@vt.edu)

                              Leaning objectives

                              Water pH has profound impacts on the pathogen survival in irrigation reservoirs and the performance of agricultural chemicals including chlorine and other disinfectants. It also affects the availability of macro- and micro-nutrients, crop quality and productivity.

                              After reviewing this module, you will …

                              • Recognize the importance of water pH for horticultural crop health and production
                              • Differentiate water pH among various water sources
                              • Recognize how water pH may vary within a runoff containment pond
                              • Develop a better understanding of what drives water pH fluctuation in such ponds, and
                              • Be able to formulate site-specific strategies to manage water pH for improved crop productivity and profit margin at the minimum cost.

                              Learning materials

                              Additional reading materials

                              • Argo, W. R. and Fisher, P. R. 2002. Understanding pH management for container-grown crops. Meister Publishing,Willoughby, OH
                              • Hong, C. X.  2013.  Water pH dictates chlorine performance. Virginia Nursery and Landscape Association (VNLA) Newsletter 83 (4):58-60
                              • Hong, C. X.  2014.  Three reasons to irrigate plants in the early to mid-morning. VNLA Newsletter 84(1):66-68
                              • 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
                              • Kong, P., Moorman, G. W., Lea-Cox, J. D., Ross, D. S., Richardson, P. A., and Hong, C. X.  2009.  Zoosporic tolerance to pH stress and its implications for Phytophthora species in aquatic ecosystems.  Applied and Environmental Microbiology 75:4307-4314
                              • Valdez-Aguilar L. A., Grieve C. M., Poss J., and Mellano M. A.  2009.  Hypersensitivity of Ranunculus asiaticus to salinity and alkaline pH in irrigation water in Sand Cultures. HortScience 44 (1):138-144
                              • 13. What are my economic perspectives of capturing and reuse of runoff water for irrigation

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                                By Dr. Jim Pease (peasej@vt.edu)

                                Learning objectives

                                Investing in rainfall and irrigation water capture for recycling may have advantages in terms of water supply security and avoiding unwanted scrutiny from government water protection programs.  At the same time, irrigation water recycling brings a greater possibility of waterborne disease, and requires careful disease management monitoring and control.

                                After reviewing this module, you will …

                                • Recognize the characteristics of Mid-Atlantic recycling nurseries and how they differ from non-recycling nurseries
                                • Develop a better understanding about irrigation recycling costs and benefits through examining case studies of Mid-Atlantic nurseries that are implementing recycling
                                • Learn about the Chesapeake Bay “pollution diet” and what it may mean for nurseries
                                • Be able to use an economic framework to assess whether irrigation recycling is appropriate for your nursery.

                                Learning materials

                                Additional reading materials

                                • Fisher, P. (ed.) 2013. Water Quality and Treatment. University of Florida IFAS Extension and Water Education Alliance for Horticulture.
                                • Cultice, A. 2013. Horticultural producers’ willingness to adopt water recirculation technology in the Mid-Atlantic region. M.S. Thesis, Dept of Agricultural and Applied Economics, Virginia Tech.
                                • Hartter, D.  2012.  Understanding consumers’ ornamental plant preferences for disease-free and water conservation labels, Department of Agricultural and Applied Economics.  M.S. Thesis. Virginia Tech, Blacksburg, VA