Ken Horst, professor emeritus of plant pathology who was best known for his research on diseases of ornamental crops, died June 9 in Ithaca. He was 85.

Horst received his bachelor’s degree in plant science from Ohio University in 1957. After earning a Ph.D. in plant pathology from the Ohio State University in 1962, he served as director of the plant pathology laboratory at Yoder Brothers Inc. in Barberton, Ohio. In 1968 he was appointed assistant professor of plant pathology at Cornell, where he continued his research on the diseases of ornamental crops. He was promoted to full professor in 1980.

“Ken was a fantastically versatile floriculture pathologist, with his academic knowledge well-enriched by experience in industry before he came to Cornell,” said Margery Daughtrey, senior extension associate at the Long Island Horticulture and Research and Extension Center. “His contributions to documenting floriculture pathology were immense, particularly in the areas of diseases of chrysanthemum, roses and geraniums, with a specialization in virus and phytoplasmal diseases.”

In addition to his research, teaching and extension responsibilities, Horst authored and co-authored more than 230 articles, books and book chapters.

“Perhaps his greatest contribution was to pick up the torch of Cynthia Westcott [Ph.D. ’32], author of the “Plant Disease Handbook,” and write the fourth, fifth, sixth and seventh editions” of the publication, Daughtrey said.

In addition to this encyclopedic reference for gardeners, diagnosticians and ornamentals pathologists, Horst authored the first editions of the “Compendium of Rose Diseases” and the “Compendium of Chrysanthemum Diseases,” as well as the second edition of the “Compendium of Rose Diseases and Pests.”

After 30 years with Cornell, Horst retired and started a private research company, H&I Agritech, with his longtime collaborator, Herb Israel. H&I Agritech was supported by a grant from the Church and Dwight Company – a major American manufacturer of household products – and focused on development of environmentally safe pesticides for disease and pest control. He received many patents for organic disease control agents and served as a consultant nationally and internationally to commercial plant industries.

Horst is survived by his wife of 52 years, Hope Thorn Horst; four children and several grandchildren.

Magdalen Lindeberg is assistant director at the School of Integrative Plan Science in the College of Agriculture and Life Sciences.