Sarah J. Pethybridge obtained her Bachelor of Agricultural Science degree with first class honors in plant pathology from the University of Tasmania, Australia, in 1995. Four years later, she was awarded her Ph.D. degree in plant pathology from the same university. Afterward, she joined the Tasmanian Institute of Agricultural Research, University of Tasmania, as a junior research fellow, working initially with the Australian hop industry. Within two years, pyrethrum pathology was also incorporated into her portfolio, and the theme of her research developed into the development and extension of integrated disease management programs across these industries. She spent 10 years with the University of Tasmania in this role, progressing through the ranks to the position of senior research fellow. Earlier this year, Pethybridge joined the Australian pyrethrum company, Botanical Resources Australia Pty. Ltd., in the position of research manager. She continues her relationship with the University of Tasmania as an honorary research faculty member.
Pethybridge has distinguished herself as a productive and innovative epidemiologist. Her work has balanced fundamental research with applied outcomes to ensure that efficient and sound disease management strategies are adopted widely by producers and other stakeholders. Pethybridge’s research has focused on areas of quantitative and applied epidemiology and has involved numerous productive collaborations with researchers in the United States. Her research has involved the development and application of novel spatiotemporal and regressions methods for description of plant disease epidemics, interactions between diseases within common production systems, and site-specific risk models for disease forecasting. In her young career, she has authored 42 peer-reviewed journal articles, 18 book chapters or review articles, 26 extension publications, and numerous conference proceedings and other publications.
Pethybridge has made substantial contributions to our understanding of the epidemiology and management of virus diseases of hop. In collaboration with the Australian hop industry, Pethybridge quantified the effect of viruses on production and used a range of methods to describe the characteristics of their epidemics in space and time. This research identified novel mechanisms by which three viruses were spread within hop yards and identified management strategies to minimize their spread. This information and the experimental approaches have since been extended to researchers and producers in the United States and New Zealand. While serving as a visiting scientist at Washington State University, funded in part by an award from the Australian Academy of Science, Pethybridge conducted comparative epidemiological studies to investigate the effect of aphid vector species on spatiotemporal characteristics of Carlavirus epidemics. Her research also led to the revision of the nomenclature of the most common ilarvirus in hop from Prunus necrotic ringspot virus to Apple mosaic virus, based on molecular evidence. Additionally, she conducted a risk analysis for two exotic fungal diseases—powdery and downy mildew—that have assisted in tightening quarantine regulations to reduce the probability of introduction of these diseases into Australia. Her contributions to the hop industry also are demonstrated by her invitation to present the keynote address at the 1st International Symposium on Humulus in 2004. Moreover, she was one of three editors for the Compendium of Hop Diseases and Pests, published in 2009 by APS PRESS.
Pethybridge has made outstanding contributions toward clarifying the etiology, epidemiology, and management of a new fungal disease of pyrethrum, ray blight, which caused substantial losses to the Australian pyrethrum industry in 2000. As a result of her research, management strategies were implemented within two years of disease identification, and economic losses from this disease have been minimized. Her complementary studies on the characterization of foliar diseases, and their epidemiology and management within the pyrethrum production system, helped to clarify their temporal fluctuations, and identified site-specific disease risk factors. She has identified four new diseases of pyrethrum, and described a new fungus, Microsphaeropsis tanaceti, that attacks this crop. This information has been combined into a disease risk management program for the Australian pyrethrum industry. This program has resulted in average yield increases of 80% and net returns of up to $3,000/ha AUD. Her research findings and management recommendations have been broadly adopted by the Australian pyrethrum industry, being implemented by greater than 90% of the industry. Moreover, Pethybridge’s collaborative approach to this problem has resulted in extensive international research efforts, with nine scientists visiting her laboratory in the last eight years, all resulting in peer-reviewed journal articles.
Pethybridge has also participated in teaching programs for plant pathology and crop health management within the University of Tasmania. Her course and teaching were awarded Teaching Merit Certificates (nominated by the participants) in 2004. She has also contributed to the supervision team of 10 graduate students. In 2003, she was awarded the Australian Institute of Agricultural Science and Technology’s Agri-Industry Award, and in the subsequent year, the University of Tasmania’s Foundation Award for Outstanding Graduates. During her Ph.D. studies, she was also awarded the Young Australian of the Year Award for Science and Technology (Tasmania).
Pethybridge has also provided outstanding service to the discipline, with leadership roles within APS, the Australasian Plant Pathology Society, and the Australian Institute of Agricultural Science and Technology. She has served as chair of the APS Epidemiology and Crop Loss Assessment and Risk Evaluation Committees, senior editor for Plant Health Instructor, associate editor for Plant Disease, and as senior editor with Plant Disease, beginning in 2010. She is also a senior editor for the journal Plant Pathology. Pethybridge has also served as the regional councilor for Tasmania within the Australasian Plant Pathology Society and for the Australian Institute of Agricultural Science and Technology, within the Executive Committee and as secretary for the Tasmanian branch.