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Paul Roy Desjardins

Professor of Plant Pathology

UC Riverside

1919 - 2003


Paul R. Desjardins, an emeritus professor of plant pathology, University of California, Riverside, died October 22, 2003, at the age of 84. Desjardins graduated with a Ph.D. degree in plant pathology from UC Berkeley in 1952 and spent his entire career as a plant virologist in the Plant Pathology Department of UC Riverside. He maintained an active research effort and departmental presence well past his retirement in 1990.


Paul Desjardins was a respected colleague recognized by all as a fine scholar and a caring teacher. He imparted a gift of respect and tolerance to all who came in contact with him. He was a gentle man without the impatient edge common among research scientists. He was a pleasant colleague to be with.


Paul Desjardins committed a large part of his research efforts to the purification, characterization, detection, and indexing of viruses of citrus and avocado and did much of the fundamental research on the Avocado sunblotch viroid, including important studies on seed/pollen transmission and symptomless carrier plants. He was a pioneer in the isolation and characterization of viruses (phage) that infect blue-green algae (Cyanobacteria) and their possible use to control algal blooms.


Desjardins earlier career coincided largely with the arrival of Electron Microscopy as a powerful tool for biological research. During the decades of the 1950-60-70’s there was rapidly increasing interest among a wide range of biologists in using this technique for the study of different organisms. Electron microscopy is a complex, demanding technique requiring great skill not only in the operation of a sophisticated instrument but often the biggest hurdle is the challenge of sample preparation. Paul Desjardins excelled in both. And to his credit he was most willing to share this dexterity with his colleagues. He was thus a valuable asset not only to his own department but to the entire campus as well.


His publications covered a wide range of topics, a testimony to his willingness to establish fruitful collaborations with other colleagues who sought and benefited from his expertise in electron microscopy. In addition to his work on plant viruses he engaged in important collaborative studies on the fine structure of other organisms (fungi, algae, insects and mites). According to Citation Index, a current but somewhat controversial tool to judge the impact of scientific contributions, his more impacting publications were on Genetic Expression in Tobacco Mosaic Virus (with William O. Dawson); on the Phycovirus Infection of Blue-Green Algae (with Robert S. Safferman); on the Sweetpotato Whitefly (with A.N. Kishaba); on Viroids in the Sunblotch Disease of Avocado (with Joseph S. Semancik) and on the Electron Microscopy of Zoospores of Phytophthora (with George Zentmyer and S. Bartnicki-Garcia).


His skill as an electron microscopist was evident in the quality of the images found in his publications and in the frequently changing display of micrographs in the hallway next to his laboratory. He enjoyed himself the most when he was in his laboratory and especially in the electron microscope room, delving into the appearance and structure of virus particles and virus crystals and exploiting all aspects of the tool.


Desjardins was greatly admired by graduate students. He taught Plant Virology Methods, for many years. His dedication to the students was immense; this training effort required countless hours of preparation of class material which he undertook with admirable enthusiasm. His curiosity about techniques of all manners enriched the experience of his students.


Paul Desjardins will also be remembered fondly by all those who visited his office, especially for his unique filing system for stacks of micrographs, letters, folders, books, and journals.


He was survived by his wife Rosemary and their children, Vincent, Chris, and Mary.


Salomon Bartnicki-Garcia

Joseph S. Semancik

Deborah M. Matthews