The APS Excellence in Regulatory Affairs and Crop Security Award recognizes outstanding contributions to regulatory plant pathology, crop* security, and trade enhancement efforts by APS members.
Dr. Scott Harper received his Ph.D. from the University of Auckland in 2009, studying resistance-breaking isolates of citrus tristeza virus. After graduating, he worked at MAF Biosecurity New Zealand, developing diagnostic tools, including a widely used qPCR diagnostic assay for Xylella fastidiosa, before resuming his citrus virus journey as a postdoctoral researcher at the University of Florida in 2010, focusing on citrus tristeza virus populations and the effect of complementation on systemic movement in the plant and vector transmission efficacy. He joined Washington State University in 2017, as an Assistant Professor in Plant Pathology, and also serving as the Director of the Clean Plant Center Northwest (CPCNW). His research program focuses on developing solutions to intractable systemic diseases in perennial crops, with an emphasis on host-pathogen and host-vector interactions. This work is critical as the Pacific Northwest is home to the largest apple, cherry, and hop industries in the U.S.
Dr. Harper has been instrumental in modernizing the CPCNW, which is one of the key facilities of the National Clean Plant Network (NCPN). This is a USDA-funded program whose mission is the development and production of virus-free germplasm, preventing the introduction and spread of harmful pests and diseases in domestic and imported propagative material. His work, in concert with other NCPN centers and USDA-APHIS, led to introduction of high-throughput sequencing (HTS) as a quarantine diagnostic tool for tree fruit and hops, and developed a diagnostic regime that accounts for seasonal plant and pathogen biology to increase the likelihood of detecting pathogens and reduce the incidence of false negative tests. This has been recognized as a model by the USDA-APHIS-PPQ. His efforts have shortened the quarantine period from four to two years while reducing the risk of introduction and spread of plant pathogens. This is most clearly demonstrated by the fact that, despite applying more rigorous HTS-based standards, the CPCNW has released more clean varietal lines to stakeholders in the U.S. in the last 7 years (551) than in the prior 21 years (404). He is also a major contributor to regulatory improvements regarding the need to properly identify or remove regulation of ‘phantom diseases’ from the USDA-APHIS-Biotechnology Regulatory Services risk analysis of plant pathogens.
One of Dr. Harper’s most significant impacts on crop security has been his work on X-disease. Within weeks of starting at WSU in 2017, he began receiving inquiries from growers and crop consultants seeking assistance with diagnosing diseases affecting cherry trees. The cause was thought to be caused by little cherry virus 2, but his investigation revealed it was the X-disease phytoplasma (‘Candidatus Phytoplasma pruni’). In 2018, he sounded the alarm at state industry meetings. His efforts spurred formation of the Little Cherry and X-Disease Task Force comprised of scientists from WSU, Oregon State University, and the USDA Agricultural Research Service as well as crop consultants, growers, and industry organizations. This group translates current research into effective management plans and educates growers on the disease and strategies to mitigate its impacts on the stone fruit industry, valued at $407 million in Washington State alone. Dr. Harper serves as the lead plant pathologist of this group, and his research on the pathogen epidemiology and host range has led to development of best management practices that have had real impacts on growers; industry surveys indicated that 89% have changed their management practices based on information received, 86% had scouted for symptomatic trees, 77% had removed infected trees, and 70% had applied vector management sprays. Over the past five years, growers who adopted pathogen management recommendations have seen a significant decrease in X-disease incidence and impacts. He led the writing of the USDA National Recovery Plan for X-disease and contributed to the production of disease factsheets, scouting and sampling guides, industry and extension panels and presentations, and grower workshops. Furthermore, early research, education, and outreach, including briefing of USDA leadership by Harper and collaborators, led to $2.5 million in congressional funding per year, since 2022, to establish a WSU - USDA-ARS research partnership to continue developing innovative methods to combat this disease.
Harper’s leadership and expertise have been instrumental in the development of effective regulatory responses to X-disease, including briefing state regulatory agencies in the Pacific Northwest USA as well as Canada on research results and risks associated with disease spread. His contributions to crop security include demonstrating the various sources of inoculum, identifying the roles of vector-mediated spread among orchards and from natural reservoirs of the pathogen and the sale and distribution of infected nursery trees across the Western U.S. The combination of growers’ experiences with X-disease and educational efforts by Dr. Harper and other task force members has culminated in increased buy-in for the critical role of clean plant programs such as the CPCNW and state plant certification programs. In turn, he transformed the capacity of the CPCNW to address this need, thereby enhancing support and protection of the $5.9 billion grape, $562 million hop, and $5.4 billion fruit tree industries in the U.S.
The tremendous impacts of Harper’s leadership and research contributions make him highly deserving of the APS Award for Excellence in Regulatory Affairs and Crop Security.
