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R. Kenneth Horst

R. Kenneth Horst

Professor Emeritus

(607) 255-7859 (voice) (607) 255-4471 (Fax)


  • Ph. D. Ohio State University
  • 1962 M.S. Ohio State University
  • 1960 B.S., Ohio University, 1957

Professional Experience

  • 1992 - present - President and CEO, H & I Agritech, Inc., Ithaca, NY
  • 1998 - present - Professor Emeritus of Plant Pathology, Cornell University, Ithaca, NY
  • 1980 - 1998 - Professor of Plant Pathology, Cornell University, Ithaca, NY
  • 1974 - 1980 - Associate Professor of Plant Pathology, Cornell University, Ithaca, NY
  • 1968 - 1974 - Assistant Professor of Plant Pathology, Cornell University, Ithaca, NY
  • 1962 - 1968 - Director, Pathology Laboratory, Yoder Bros., Inc., Barberton, Ohio

Research Interests

The major objective in my research program has been to develop a good mix of basic and applied research that would complement each other in terms of providing a basic understanding of the nature of host-pathogen interaction which would not only be a significant contribution to the field of plant pathology but also provide useful practical application to the ornamental industry. I believe that the research efforts from my laboratory have been successful in accomplishing this objective. Efforts have been mainly directed toward diseases caused by virus and virus-like agents and vascular wilt pathogens. These diseases are very difficult to control and are very easily spread along with plant propagules. Their control has mainly been accomplished by using virus-indexing and culture-indexing procedures carried out by large commercial propagators which provide plants for sales that have been tested for their freedom from these pathogens. These programs are expensive to run; however, they are the best available control. Thus my efforts have concentrated on 1) development of new and more efficient detection procedurs for viroid/virus, mycoplasmalike organisms, and vascular wilt pathogens; 2) determination of optimum conditions for detection; 3) understanding the basic nature of the infection process in diseases caused by viroids; and 4) development of other methods of control of viroids.

Professional Organizations

  • American Phytopathological Society
  • International Society of Plant Pathology
  • International Society of Horticultural Sciences
  • Committee Tissue Culture Association
  • American Association for the Advancement of Science
  • Society of American Florists

Honors & Awards

  • Sigma Xi Gamma Sigma Delta 1996, Awarded medal from The Warsaw Agricultural University at the 75th Anniversary for the Faculty of Horticulture for "Contributions to the Faculty and the College".
  • 2000, Awarded "Distinguished Citizen Award" by Massillon Washington High School, Massillon, Ohio, the high school from which I graduated in 1953.

Significant Publications

  • Horst, R. K. and R. A. Cloyd. 2007. Compendium of Rose Diseases and Pests. 2nd Edition. 83 pp. APS Press, St. Paul,. MN.
  • Horst, R. K. 2007. Cynthia Westcott, The Plant Doctor. In: Pioneer Women in Plant Pathology. pp. 227-237. APS Press, St. Paul, MN.
  • Horst, R. K. 2008. Westcott's Plant Disease Handbook, 7th Edition. Springer Science, Dordrecht, The Netherlands. 1343 pp.
  • Romaine, C. P. and R. K. Horst. 1975. Suggested viroid etiology for chrysanthemum chlorotic mottle disease. Virology 64:86-95.
  • Horst, R. K. 1975. Detection of a latent infectious agent that protects against infection by chrysanthemum chlorotic mottle. Phytopathology 65:1000-1003.
  • Horst, R. K. and S. O. Kawamoto. 1980. Use of polyacrylamide gel electrophoresis for detection of chrysanthemum stunt viroid in infected chrysanthemum tissues. Plant Disease 64:185-188.
  • Horst, R. K. 1983. Compendium of Rose Diseases. 72 ppp. APS, St. Paul, MN. Horst, R. K. 1990. Westcott's Plant Disease Handbook, 5th Edition. Van Nostrand Reinhold Publishing Co., New York, NY. 953 pp.
  • Horst, R. K., S. O. Kawamoto, and L. L. Porter. 1992. Effect of sodium bicarbonate and oils on the control of powdery mildew and black spot of roses. Plant Disease 76:247-251.
  • Horst, R. K. 1997. Fungicides for the future. Grower Notes, Society of American Florists. 2(2):1-3.
  • Horst, R.K. and P.E. Nelson. 1997. Compendium of Chrysanthemum Diseases. 88 pp. APS, St. Paul, MN.