Reflections on Jay Jacobson (1934 – 2022)

by | Sep 28, 2022

Jay Jacobson looks at leaves on a plant in a greenhouse.

In this picture from BTI’s 1984 annual report, Jay Jacobson investigates the retention of fungicide deposits on leaves after exposure to acid rain.

We at BTI were sad to hear of the passing of Dr. Jay Jacobson, a plant physiologist who spent 35 years conducting research in the Environmental Biology group at the Institute.

During the 1960s and 1970s, scientists began to recognize that the most serious and widespread effects of air pollutants on vegetation were from air and cloud masses that produced photochemical smog and acidic precipitation. Consequently, Dr. Jacobson shifted his research to study plant response to ozone and the sulfuric and nitric acids in rain, primary plant-damaging components of photochemical smog and acidic precipitation, respectively. As recognition increased of the important interaction between pollutants and environmental conditions, his research also shifted from the use of indoor plant exposures in controlled environment chambers to field exposures using open-air plots to expose crops or tree seedlings to controlled concentrations of pollutants and, finally, to large outdoor chambers so whole trees could be exposed to controlled amounts and concentrations of acidic precipitation.

Jay published numerous articles in scientific journals on methods for the analysis of fluorides in vegetation, the combined influence of ozone and sulfur dioxide on crop plants, plants as indicators of pollution, the effects of sulfuric and nitric acids in rain on red spruce, and the use of scientific information in the development of public policies for the control of air pollution.

Jacobson filled a Professional Term Appointment as Plant Ecologist with the Division of Biomedical and Environmental Research at the Department of Energy Headquarters in Germantown, Maryland, during 1977 and 1978. He had academic appointments as adjunct associate professor in the graduate faculty of Cornell University through the Department of Natural Resources and the Fields of Environmental Quality and Environmental Toxicology. He was a statutory member of the Clean Air Science Advisory Committee of the U.S. Environmental Protection Agency (EPA), a member of competitive grants panels for the EPA and U.S. Department of Agriculture, and a member of several professional societies. He helped organize and facilitate scientific meetings and gave lectures in the departments of Agronomy, Biological Sciences, Natural Resources, and Plant Pathology at Cornell University.

He retired at the end of 1996 as Plant Physiologist Emeritus after working at the Boyce Thompson Institute for 35 years.

Jay loved traveling and visited many countries around the world presenting papers at scientific conferences. After he retired, Jay pursued interests in theater and improvisation, sailing, trained as a volunteer mediator, volunteered at Head Start, and was very active in community life at EcoVillage at Ithaca. In North Carolina, he volunteered in a prison Buddhist meditation group, in Hospice, with Meals on Wheels, and with MY Neighbors. Although he was quiet about it, Jay was clearly a very community-minded human being. He is survived by his wife Ruth, his sister Karen Sack, son Frank Jacobson, daughters Kathy and Karen, and grandchildren Zachary, Andrew and Alyssa.

Since his passing, some of Jay’s former colleagues have shared reflections, which we are pleased to share with you below. If you would also like to share your reflections on Jay, please email them to


Ariena H.C. van Bruggen, Emeritus Professor Plant Pathology, Emerging Pathogens Institute, University of Florida

In the 1980s, Dr. Jay Jacobson had a special interest and expertise in effects of acid rain on plant diseases in agricultural crops and forests. He had received a grant to investigate effects of acid rain on wash-off of fungicides from leaf surfaces, and I was hired in November 1984 as a post-doctoral associate under his guidance in the Environmental Biology Group of the Boyce Thompson Institute. This was before I had finished my PhD at Cornell University in January 1985. He was very supportive and gave me lots of freedom to develop my own research program. Moreover, he allowed his research assistant Joe Osmeloski to work with me full-time. Joe had excellent knowledge of and experience in atomic absorption spectroscopy and gas chromatography. This was essential to measure fungicide residues on leaves. Jay helped me to realize that it was important to measure the acidity of rain droplets in situ, on the leaf surface. And I had some experience establishing an infection-cycle of Phytophthora infestans causing late blight on potato leaflets.

So, together, we developed a method of producing single-leaf cuttings of potato plants that we sprayed with fungicides, exposed to simulated acidic rain on a turntable, and inoculated with P. infestans under controlled conditions. After experiments with various fungicides, we realized that wash-off rates were simply related to pH of the fungicides themselves, hydroxide fungicides being washed off more easily by acidic rain than others such as carbamates. Thus, Jay allowed me to shift our focus on effects of acidic rain on spore germination, infection efficiency and sporulation of two potato pathogens, causing early and late blight. That turned out to be more interesting research, showing that effects of acidic rain depended on its relative effect on the pathogen versus the host, affected by the timing of the acid rain application. Yet, we returned to effects on wash-off of a fungicide (as required for the grant), namely metalaxyl, and developed a model for the attenuation curves at different pH levels of the applied rain. The model was suggested by Dr. Len Weinstein, and to my dismay I discovered while writing this reflection that he was not included as co-author on the resulting paper.

Before my arrival at BTI, Jay had worked with two other postdocs (one after the other), John Troiano and Earle Butterfield, on effects of simulated acidic rain on late blight development on potatoes in two field experiments. They had used slightly different disease assessment methods. It was therefore complex to analyze the data together. However, Jay stimulated me to do this, so that the data would not get lost and that I would have an additional paper in my early career.

After being a post-doc for 1.5 years, the grant ran out, and I could start an assistant professor position at UC Davis in May 1986. There would be one month of salary gap, but Jay agreed to fill this gap. In return, I initiated an experiment on the effect of acid rain on ice-nucleating bacteria and frost sensitivity of fir trees (a subject close to Jay’s interest). Unfortunately, this research could not be finalized.

Reflecting on my time at BTI, I feel very much indebted to Jay Jacobson. He was an excellent mentor, allowing me full freedom, and also helping me in three crucial ways: arousing my interest in environmental biology, providing advice on detailed measurements of fungicide residues and pH of droplets on leaf surfaces, and providing me with the assistance of an excellent technician. I remember Jay as a very friendly, helpful advisor, facilitating the contacts with other BTI scientists, and as a good human being providing extra salary for a month to bridge the gap between two jobs.

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