Dr. Harry A. J. Hoitink was born in the Netherlands. He received an Ing. degree from the Hogere Landbouw School in Roermond, the Netherlands; B.S. and M.S. degrees in plant pathology from MacDonald College of McGill University in Montreal, Canada; and a Ph.D. degree in plant pathology-bacteriology from the University of Wisconsin-Madison. His highly meritorious career began at The Ohio State University in Wooster in 1967, where he currently serves as both professor of plant pathology and professor of environmental sciences graduate studies program. Dr. Hoitink is best recognized for his landmark contributions to the understanding of the role of soil organic matter in natural suppression of diseases caused by soilborne pathogens. This has been achieved through careful and diligent integration of basic and applied research among the disciplines of plant pathology, soil microbiology, and microbial ecology. His work with composts and suppressive peat mixes has clearly revolutionized the ornamentals industry throughout the world.
With his students, Hoitink first began to unravel the mystery of biocontrol agents by defining the conditions that consistently led to induced microbiostasis and natural suppression of root rots caused by Pythium, Phytophthora, and Rhizoctonia spp. Moreover, they showed that controlled amendment with specific biocontrol agents, including fungal and bacterial mycoparasites, was essential to consistently induce suppression of R. solani. This led to the idea of using composts as a foodbase for biocontrol agents, and today this approach to biological control is becoming a reality.
A unique and significant aspect of the research was the elucidation of the importance of the decomposition level of organic matter and the microbial species composition essential for biological control. His innovative methodology for assessing microbial activity has now been adopted by numerous scientists studying microbial ecology.
Dr. Hoitink and his colleagues have used nuclear magnetic resonance spectroscopy to nondestructively characterize the change in chemistry and biological energy available in the substrate as bacterial taxon composition changed and suppression was lost. Their work on microbial community biomass and activity is cited heavily not just in plant pathology, but in the general field of microbial ecology.
More recently, Hoitink’s group has demonstrated that naturally suppressive composts consistently induce systemic resistance to Pythium root rot, whereas highly decomposed peat substrates failed to protect plants.
Dr. Hoitink is in great demand nationally and internationally as a lecturer and research development consultant. Expanding beyond plant pathology, he has developed a computer-controlled system for composting municipal sludges that has been adopted widely in the United States and abroad. In 1988, he received the first National Award for Research on Composting from the U.S. Environmental Protection Agency. He is a Fellow of APS.
His enthusiasm for science and facilitation of innovative and holistic approaches to biological control are truly infectious. The research program developed under his leadership is a truly exceptionally example of how balance between fundamental and applied research can make major contributions to the advancement of science and also have a highly significant positive socio-economic and environmentally sound impact on a major plant industry.