George Salt

Entomologist specialising in parasites

George Salt, entomologist and ecologist: born Loughborough, Leicestershire 12 December 1903; Fellow, King's College, Cambridge 1933-2003; University Lecturer in Zoology, Cambridge University 1937-65, Reader in Animal Ecology 1965-71 (Emeritus); FRS 1956; married 1939 Joyce Laing (died 2002; two sons); died Cambridge 17 February 2003.

George Salt was first and foremost an entomologist, but, since much of his scientific life had been concerned with the interplay between parasites and their hosts, he described himself as an ecologist. He developed very successful methods for controlling pests by introducing other insects that parasitised them. His approach was eclipsed by the widespread introduction of chemical insecticides, but his contributions seem extraordinarily prescient now in an environmentally conscious age.

I first met him in a zoology supervision which he gave to me and another newly arrived undergraduate at King's College, Cambridge. He was formal and more than a little intimidating, but we invariably left his supervisions wanting to read everything to which he had referred. He had a passionate desire to be clear, speaking in succinct, perfectly formed sentences. But behind an upright and conservative façade lay a very different person, both mild and kind, whose thinking was adventurous and a shade romantic. It was these latter qualities, largely buried from the sight of many of his colleagues, that made him so stimulating to us undergraduates.

The tension between his orderly and romantic sides was ever-present and may well have had its origins in the very different personalities of his parents. He described his mother as a firm disciplinarian who managed the family affairs. She was more ambitious and aggressive than his father who, by contrast, was considerate, bookish, painted landscapes in oils, was a skilled photographer and a good craftsman in wood; he played the violin, sang and took pleasure in gardening.

His father had run two grocery shops in Loughborough, where George was born in 1903, but, when he was seven, the family moved to Calgary and his father took a job with the Canadian Pacific Railways. Life was tough for them but his mother was determined that her four children should have a good upbringing. George earned money to pay for his own education from a paper round after school which he kept going throughout the Canadian winters.

Throughout his life George Salt maintained his thrifty habits and he said he frequently had anxiety dreams about being impoverished. He was opposed to getting a mortgage and so he saved for a house; but rising Cambridge house prices remained tantalisingly just ahead of what he had saved. Finally, the family moved into a house in Barton Road when he was 57. Their house was austerely furnished but provided the scene for many hospitable lunches and teas. He and his wife, Joyce, went out of their way to bring to their house visitors from abroad, young newly elected Fellows from his college and the students he taught with such devotion and care.

Salt graduated in science from the University of Alberta at Edmonton. Having collected insects since he was 11, he now properly became an entomologist, working for a PhD at Harvard. His thesis was on the parasitism of bees and wasps by another insect called Stylops which developed inside them and caused them to be de-sexed, thereby ensuring greater resources for itself. His first post-doctoral job was for the United Fruit Company in Colombia, where he discovered a biological method for controlling the devastating banana-beetle. It was a lawless place and he went about armed – a fact that invariably surprised those who knew him later in his life.

After a further period at Harvard he decided to return to England, joining the Institute of Entomology at Farnham Royal. He discovered parasites for wheat-pests widespread in Canada, but he wanted to get back to basic research and moved to Cambridge in 1931. Two years later he was elected a Fellow of King's, and became University Lecturer in the Zoology Department in 1937.

During the Second World War he worked at Cambridge for the Ministry of Agriculture on the control of wireworms. He also became Lay Dean of King's and from 1945 to 1951 was Tutor for Advanced Students. In 1948-49 he took a period of leave in East Africa, where he collected insects assiduously on the slopes of the great volcanoes. This research proved very productive and was probably the type of work he loved most.

He was very far from being a mere collector, though. His laboratory work was exquisite. In a long series of papers he described in meticulous detail the behaviour of the tiny insect parasite Trichogramma; he showed how Trichogramma uses two different senses to detect whether or not a moth egg had already been parasitised.

Salt was elected a Fellow of the Royal Society in 1956 and was made Reader in Animal Ecology at Cambridge in 1965. Later he turned to an experimental analysis of the mechanisms by which some insects disable their parasites and described this in an elegant monograph, The Cellular Defence Reactions of Insects (1970).

GS (as he liked to be called by those close to him) was physically strong and loved mountaineering. He had many other interests which he developed in retirement. Calligraphy became his passion and he devoted himself to discovering the tools for writing used in many different cultures and produced examples of as many forms of handwriting as he could find. He also illuminated manuscripts, and painted in watercolours and oils. He gave his illustrated book on Bacon's Essay on Gardens and his collection of calligraphy and writing implements to the Fitzwilliam Museum. His beautiful Handwriting and Gardens was given to the Royal Library at Windsor. He left much else, including his own house, to King's, which had been the pivot of his life after he arrived in Cambridge and where he had been a Fellow for 70 years.

His marriage in 1939 to Joyce Laing, his first research student and later a Fellow of Newnham College, was extraordinarily happy. She died nine months before him. Able to do very little but recite poems to himself, this remarkable, naturally active man found his last year a torture but his clear head and immaculate memory remained with him to the end.

Patrick Bateson