Dr. R.S. Mehrotra was born on 4th January, 1937 in Village Anantram, District Etawah, U.P. He did his M. Sc and Ph. D from the University of Saugar, Sagar (Now known as Dr. Hari Singh Gaur University), M.P. in the year 1958 and 1961 respectively. For his Ph.D degree he worked on the foot rot and leaf rot of Piper betle and their control under the supervision of Late Prof. S.B. Saksena. He joined the University of Saugar, M.P.in the year 1964 as Assistant Professor and then later shifted to Kurukshetra University, Kurukshetra in year 1970 as Reader then Professor in the year 1978. He retired from Kurukshetra University in the year 1997. He was Post Doctoral Fellow at the University of Western Ontario, London, Ontario, Canada in the years 1968-1970 and worked in collaboration with late Prof. C.J. Hickman on the biology of Phytophthora Zoospores in soil using fluorescent brightenersand fluorescent microscopy. He was also a Fulbright Fellow at the University of California, USA Riverside campus for a short duration in the year 1979 and worked in collaboration with world authority on Phytophthora, Prof. G.A. Zentmyer.
Professor Mehrotra was a Fellow of the National Academy of Sciences (Allahabad). He was elected President of the Indian Phytopathological Society in the year 1990. He was also elected President of the Indian Society of Plant Pathologists in the year 1992 and President of the Mycological Society of India in the year 1996. He was elected President of the Botany Section of Indian Science Congress in the year 1997 and is a recipient of the Birbal Sahni Gold Medal of the Indian Botanical Society in the year 1998.
The main thrust of his research work has been on Phytophthora diseases of various crops and fungal soil borne diseases and bio-control of plant pathogens. He has authored four books viz. Plant Pathology (1980), An introduction to Mycology (1990) a monograph on Phytophthora Diseases in India (2001) and Principles of Microbiology (2009).Professor Mehrotra has written several review articles and published more than 200 research papers in national and international journals.