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Dr. Pierce A. Paul

Dr. Pierce A. Paul was born and raised in Guyana, South America. He earned his undergraduate degree in Agronomy and M.S. in Plant Pathology from the Federal University of Viçosa, Brazil, under the guidance of Francisco do Vale, and his Ph.D. in Plant Pathology (with a minor in Statistics) from Iowa State University (ISU), under the guidance of Gary Munkvold. In 2003, Paul joined Patrick Lipps and Larry Madden in the Department of Plant Pathology at The Ohio State University (OSU) as a postdoctoral researcher. In 2006, he was hired as an assistant professor at OSU, with 60% research and 40% extension responsibilities. He was promoted to associate professor in 2012. Over the past 10 years, Paul has made several major contributions to the epidemiology and management of diseases of field crops, initially at ISU on gray leaf spot of maize (caused by Cercospora-zeae maydis), and then at OSU on Fusarium head blight of wheat (FHB, caused by Fusarium graminearum).

Paul’s work has significantly increased our understanding of FHB, the most economically important disease of cereal crops in the US since the stem rust epidemics of the 1950s. Through the US Wheat and Barley Scab Initiative (USWBSI), Paul has been a leading member of several research teams studying the epidemiology and management of the disease and the concomitant DON toxin produced by the pathogen. Using his expertise in statistics, he has assisted with the development and coordination of multi-state projects and quantitative synthesis of research findings. Some of his most significant contributions resulted from the use of meta-analysis and other contemporary statistical approaches to: combine results from multiple studies to characterize the relationship between FHB index (field severity) and DON; evaluate the efficacy, stability, and economics of FHB and DON management strategies; and quantify grain yield and quality losses caused by FHB. Through meta-analysis, Paul and colleagues showed that there is a significant positive, linear relationship between FHB and DON, and a significant negative straight-line relationship between FHB and grain yield. The strength of the index/DON relationship was greater for spring wheat compared to winter wheat; the mean DON level at a given level of disease was higher for spring than winter wheat; and there is DON contamination even when visible FHB disease index is 0. The relationship between relative yield loss and index was fairly consistent across studies, varieties and wheat class. Through his work on FHB, Paul has become a leading authority on meta-analysis and quantitative research synthesis in the agricultural sciences.

Paul and collaborators have also used meta-analysis to quantify the efficacy of integrated FHB and DON management strategies, with results demonstrating: poorer control of DON compared to FHB with fungicide alone; better control with genetic resistance alone than fungicide alone; and 20-25% better control of both FHB and DON with fungicide + resistance than with a single strategy. Based on nonparametric analyses, Paul and colleagues showed that an integrated management approach was more stable across environments than fungicide or resistance alone, and that the combined effect of fungicide and resistance was additive in terms of percent control. Paul’s lab also demonstrated that the use of modified grain harvesting strategies is an effective approach for improving the quality of wheat grain harvested from FHB-affected fields, and that the integration of fungicide, genetic resistance, and grain harvesting strategies could be economically feasible for FHB and DON management. Meta-analysis was also used to show that although fungicides tend to be most effective against FHB and DON when applied at flowering, applications made several days after flowering may be just as effective with the best fungicides, providing producers with flexibility in the timing of fungicide application. Findings on the efficacy, stability, and economics of FHB management programs can be used by producers to make more informed management decisions.

Paul’s research has provided insights into many aspects of the epidemiology of FHB. He and colleagues showed that spores of F. graminearum are not only wind-disseminated but also splashed dispersed within the wheat canopy, and that rain-splash is sufficient to transport spores from surface residue to the wheat spikes where infections occur. They showed through polynomial distributed lag regression and linear mixed model analyses that the density of spores on wheat spikes was significantly related to profiles of atmospheric moisture, temperature, and rainfall over 8-day periods. Paul has made major advances in the study of moisture effects on DON accumulation. He demonstrated that not only the amount, but also the timing and pattern of moisture affect: DON, the risk of DON exceeding critical thresholds, and the relationship between FHB and DON. He showed that certain patterns of intermittent post-flowering mist lead to higher DON for a given level of FHB than consecutive days with mist. The risk of DON exceeding thresholds established by the FDA was just as high with intermittent as with consecutive days with mist. Models of relationships among weather variables, spore density, FHB, and DON from these and related studies may be used to refine prediction models currently being developed, validated, and deployed nationally through collaborations among the Paul and Madden labs at OSU and the De Wolf lab at Kansas State. Paul’s current disease prediction work builds on his significant Ph.D. research, where he developed models for gray leaf spot risk that can be used to help guide hybrid selection and in-season fungicide application decisions.

Over the last 10 years, Paul has been extremely productive, with 57 peer-reviewed journal articles, two book chapters, and numerous abstracts and papers in proceedings. He has given more than 35 invited presentations nationally and internationally. As an advisor/co-advisor, he has contributed to the training of 10 graduate students, three postdocs, and five visiting scholars. He is very active nationally, serving as: Senior Editor for Plant Disease and reviewer for several other journals; member of the USWBSI Steering Committee and National Wheat Improvement Committee; Chair of the FHB Integrated Management Coordinated Project Committee; and member and past chair of the APS Epidemiology Committee and the USDA NCERA184 committee (Management of Small Grain Diseases).