Project Approaches

Total System

Plant health is an important link in the chain that forms the ornamental horticultural industry. This project addresses the total system from producer to consumer with a clear focus on crop health and its effect on prices that consumers will pay. This industry produces and distributes a live commodity, the aesthetic value of which is retained only if the plants meet the needs and expectations of the consumer. Thus, crop health at production facilities is crucial to the health of the system. Specifically, this project targets species of Phytophthora and Pythium, two groups of destructive pathogens that affect numerous ornamental plants during crop production and that can be carried through the supply chain to plants purchased by the consumer. Among them are three plant pathogens subject to federal quarantine: Phytophthora ramorum, P. kernoviae and P. alni.

Biological Solutions

This project attacks a fundamental issue associated with current fungicide-based disease management programs. Fungicides only slow pathogen spread; they cannot cure infected plants. Fungicides may temporarily prevent infected plants from exhibiting disease symptoms at production facilities, only to be expressed later in the supply chain or at the ultimate planting site. Plants undergo tremendous stress in delivery trucks, garden centers, and during installation into the landscape. Meanwhile, pathogens grow unrestricted when the fungicide naturally breaks down. In the summer of 2004, two landscapers in the Tidewater area of Virginia purchased 50,000 petunias from a local nursery. All petunias died within 2 weeks of planting. This loss was due to root and crown rots caused by Phytophthora nicotianae that had begun but went undetected during production. The landscapers were unable to recover the cost of plant materials and they lost that landscaping contract business permanently. A fungicide-based program could have prevented some of the losses but is not environmentally sustainable and poses a health hazard to farm workers and the general public.

The focus of this project is to integrate crop health protection strategies into ornamental plant production systems that will eliminate or greatly reduce the presence of plant pathogens during production or continue to suppress the target pathogens at garden centers and in the final planting site. This project will significantly increase the understanding of water quality dynamics, its impact on plant pathogens and their interactions with other microbes in irrigation systems. This new knowledge will be used to develop BMPs that reduce sources of inoculum and negate the pathogen dissemination via recycling irrigation systems.

Multidisciplinary Team

Diverse expertise is key to addressing sustainable crop health protection, water shortage and water quality issues, and the economics of crop production effectively. The project team includes biologists, engineers, economists and information technologists. Plant pathologists and horticulturists from multiple institutions across the nation work together to understand water quality dynamics and plant pathogen aquatic biology in order to develop BMPs. Agricultural engineers determine whether the BMPs are technically compatible with existing irrigation systems or how existing systems can be modified in order to implement the BMPs. Economists estimate changes in production costs related to usage of recycled water and reduced use of fungicides. They also assess the potential revenue enhancements gained through reduced crop losses and improved crop health. They examine the environmental and social benefits of adopting these new BMPs. Information technologists expedite BMP delivery to the end users while promoting internal team communications and public outreach activities.

The team interacts in ways that make the sum greater than the parts. This is accomplished through annual project meetings, semi-annual web conferencing and regular exchanges through a project collaboration website.

Industry Partnership

This project is industry-driven, with many growers and their associations involved at every stage of research and outreach. An advisory panel consisting of growers, retailers, landscapers, and executives of their professional associations meets with the team regularly to discuss project progress and provide feedback on future directions of research and extension programming. Some selected growers cooperate closely with the project team, assisting in on-farm water quality monitoring, water sampling, plant pathogen baiting, and providing plants for use in experiments. Other growers and consumers participate in Focus Groups that meet with the economists to help them determine the baseline of production costs and revenues.

This partnership is vital for the technology transfer phase of this project. There are many existing venues organized by industry groups that are effective platforms for knowledge and technology transfer. These include the annual Pest Management Conference (organized by the American Society of Florists), the ANLA Management Clinic (the American Nursery and Landscape Association), the Southern Nursery Association Research Conference, and the Mid-Atlantic Horticulture Short Course.

A full range of other extension and outreach activities will be conducted in collaboration with the industry to assure that producers, consumers, and other relevant audiences receive accurate and appropriate information and education on the BMPs developed through this research. Activities will include oral presentations and workshops at producer meetings, field demonstrations at cooperator facilities, and publications in trade magazines, journals, and extension media. Electronic media, including a new online Knowledge Center to be developed through this project, and eXtension will be used to deliver short videos and educational modules to producers. Information and education will be delivered to consumers through these websites as well as indirectly through train-the-trainer activities with Master Gardeners.