My father, John Tomlinson, who has died aged 84, was a plant pathologist and virologist who, in the early 60s, was the saviour of the British watercress industry, which had been gravely affected by a disease called crook root. Many had tried and failed to find a way to solve it. John was able to prove that it was a fungus and, through dogged experimental work, discovered that trace amounts of zinc – one part in 20m – were sufficient to kill it.
John was born in Birmingham, the son of Harry and Ellen Tomlinson. His father had ambitions for John to attend university, but he died when John was a 15-year-old pupil at Saltley grammar school. John had dreamed of becoming a doctor but this now seemed impossible. Instead, with the help of his local church, small bursaries and working in various factories during school holidays, he scraped together enough to support himself while studying biology at Birmingham University from 1944. There, he became fascinated with botany and realised that in fighting plant diseases, fungal and viral, he could contribute to improvements in global food production and make a difference to whole populations.
His first job was at Rothamsted agricultural research station in Hertfordshire. There, he learned the methodical, painstaking skills that would stand him in good stead for his career in scientific research, the bulk of which took place at the National Vegetable Research Station at Wellesbourne, Warwickshire (now Warwick Horticulture Research International). He tackled diseases of lettuce, tomato, cucurbits, brassicas, rhubarb and many more – and found ways to treat them.
In 1958 John took his first assignment in north America, at the University of Wisconsin. Spells at the University of California, at Davis and Berkeley (the latter on a Fulbright scholarship) followed. He lectured at universities and conferences throughout the world and made warm, enduring scientific contacts in Australia, Israel, the Netherlands, Italy and Morocco. He collaborated on numerous projects and published, contributed to and edited hundreds of scientific papers, many of which are still cited today. Frustrated by cuts in research funding under the Thatcher government, he took early retirement in 1986.
A mad-keen sportsman, John captained his school rugby team, played excellent snooker, golf and cricket, and followed Aston Villa FC. His marriage to Janet ended in divorce. He is survived by me, my brother, Paul, and four grandchildren, Cleo, Rupert, Alex and George.