Obituary:  John Michael Thresh – on lifelong war with plant viruses.

John Michael Thresh, aged 84 years old, died on Thursday 12 February 2015 at the Pembury Hospital Tunbridge Wells in the UK following his battle with cancer. He leaves his wife, Peggy, four sons, four grandsons and four grand-daughters. Known as Mike Thresh to family and peers, the career of Professor Thresh spanned more than 60 years.

Mike came from a farming background in the north of England and spent much of his childhood on the family farm during World War II (1939–1945). This was before the days of full mechanisations and he can claim to have ploughed with horses and harvested cereals for threshing by steam power. His mother harboured ideas of having a "blood and guts" veterinarian in the family but a career in agricultural research was always the preferred option!

Mike took a first degree in botany at Imperial College, University of London, in 1952, in the days of Professors W. Brown and F. G. Gregory. In the university vacations, he worked as a student at the East Malling Research Station and walked in the Yorkshire Dales. He spent a year with plant virologists in the Plant Pathology Department at Rothamsted Experimental Station as a Colonial Research Scholar. During this period there was an opportunity for fieldwork in East Anglia on the control of sugar beet yellowing viruses, using one of the first organophosphate insecticides to be made available for use in agriculture.

His first assignment overseas was in Ghana and Nigeria (1953–1960) on the epidemiology and control of cocoa swollen shoot disease as one of the team of virologists at the West African Cocoa Research Institute. After seven years in West Africa, he returned to England, bringing with him a wife and baby, and followed a similar career focussing on virus diseases of hop, blackcurrant, and other fruit crop species at East Malling Research Station. These studies and contributions on general epidemiological concepts led to a University of London PhD and DSc, as well as a Queen's Award for Technological Achievement to East Malling and the Department of Hop Research, Wye College. This was for the development and deployment of virus-free clones of improved hop varieties.

While Mike was a staff member at EastWhile Mike was a staff member at East Malling, a 3-month assignment to Ethiopia in 1971 for FAO was followed by other consultancies and advisory visits on behalf of FAO, the British Council, Overseas Development Administration (ODA), and several international agricultural research centres. These led to a renewed acquaintance on cocoa swollen shoot disease and the Cocoa Research Institute of Ghana through a project funded by ODA, and then to a UK-based appointment as plant virologist with the ODA Corps of Specialists. East Malling continued to be the base for many overseas forays into Africa and Asia until plant pathology was included in the remit of the Natural Resources Institute (NRI) and the transfer was then made to Chatham Maritime and the University of Greenwich. Quasi-retirement and an honorary position as Professorial Research Fellow at the University of Greenwich came in 1998 after a 5-year contract as senior virologist at NRI.

Mike was an active member of several scientific societies: he served on committees and councils of the Society for General Microbiology, the Biological Council, the Association of Applied Biologists (AAB), the Federation of British Plant Pathologists, the British Society for Plant Pathology (BSPP), and the International Society for Plant Pathology (ISPP). He edited/co-edited eleven books/conference proceedings and was Programme Secretary of the AAB (1973–1980), President of BSPP (1990), and Chairman of the International Committee on Plant Virus Epidemiology (ICPVE) of ISPP from its inception in 1979 until 1999. Mike was elected as Honorary Member of BSPP in 2005, and in 2012 became the second recipient of the Golden Cassava Award of the Global Cassava Partnership (GCP) for the 21st Century.

Mike's overseas experience spanned more than 40 countries, but he was especially knowledgeable on the virus problems of crops in Africa, where his experience was second to none. He published more than 200 papers, reviews, and book chapters. Many relate to his own research on the epidemiology and control of viruses of specific crops. These include cacao, hop, temperate fruits, cassava, and a wide range of other tropical crops. Mike had a special love for cassava and he was undoubtedly the best epidemiologist for cassava viruses.  He had the chance to work with pioneer cassava virologists and cassava breeders in Africa, who played a key role for a better control of cassava viruses in Africa.  Forty or so of his publications are concerned with general epidemiological principles, including several chapters in Annual Review of Plant Pathology and Advances in Virus Research. There have also been the series of special issues of the Elsevier journal Virus Research, which contain papers based on material presented at previous International Plant Virus Epidemiology (IPVE) Symposia and edited by Mike together with conference organizers. Mike was described as an ‘editorial genius’ for his ability to take drafts of papers and shorten them in half whilst adding invaluable additional points. Mike contributed much to our knowledge of plant virology, both within the UK and overseas, and was a tireless advocate, supporter, and promoter of plant pathology.

Mike stressed the importance of field work and a ‘hands on’ approach to research and he deplored the lack of it among so many scientists. He emphasized it was essential to see crops and plants in situ to get a holistic understanding of the epidemiology. However, he was pleased to be responsible for establishing the ISPP Plant Virus Epidemiology Committee at the Munich Congress in 1979 at a time when the more "biological" aspects of plant virology were in danger of being swamped by those with a more biochemical approach. This initiative led to the organization of 12 IPVE international conferences and the series continues with a 13^th conference to be held in France in 2016.

Mike dedicated his life for helping the poor in developing countries. He worked tirelessly to bring about a deeper understanding and control of several plant virus diseases such as cocoa swollen shoot virus in West Africa, rice tungro and yellow mottle viruses in Asia and cassava mosaic disease pandemic in East Africa. His work in Uganda led to the understanding and control of cassava mosaic virus pandemic, which had devastated crops and induced widespread famine in Uganda in the 1980s-1990s. Ugandans remember him for his remarkable contribution in controlling the epidemic and restoring food security.

Figure Legend: Cassava plants infected by whitefly transmitted mosaic virus (left).  Cassava plants grown from an infected stem cutting showing severe mosaic symptom and no root yield (centre), and Professor Mike Thresh discussing with a farmer the meagre production from a household planting totally affected by CMD (right).

Mike and his wife, Peggy, a physiotherapist, have over the years “accumulated” four sons, four grandsons and four grand-daughters. They had a wide range of outside interests including sport, the countryside, music and travel. Several of their trips have been linked with assignments or conferences abroad, including some in Ethiopia, Costa Rica, Malaysia, Ghana, Ivory Coast, the US, and North Yemen.

Mike has no special ‘words of wisdom’ to impart as the recipe for personal happiness and fulfilment. However, he did stress the value of having a supportive wife and family and the merits of a long and exciting career in research without the necessity of taking on the burdens and distractions of administration.

A memorial service is planned for 18 March at 12pm at St. Michael's Church in Maidstone for family, friends and colleagues to say a final goodbye to superstar plant virologist Mike, who worked tirelessly to increase the food security of African farmers.

Updated from an original article published on the occasion of Honors to Professor Mike Thresh, on 29th Feb 2013, during the 12th IPVE Symposium in Arusha, Tanzania.