Australian Dictionary of Biography

John Mann, 1970

Queensland State Archives, 24471

John Mann (1905–1994), entomologist, was born on 13 August 1905 at Greenmount, near Toowoomba, Queensland, second son of John Edward Mann, a locally born farmer, and his Sydney-born wife Millicent, née Tucker. His father died the same year and his mother, aged only nineteen, took the boys to Sydney, where she married Albert Croucher in 1909. It is not known where John went to school. He worked as a shop assistant and collected insects in his spare time. His love of butterflies brought him into contact with G. A. Waterhouse, who paid him to collect and breed them.

Recommended by Waterhouse, Mann was appointed on 8 February 1923 as a laboratory assistant with the Commonwealth Prickly-Pear Board and posted to Biniguy Field Station, near Moree. The next year he was transferred to the program’s headquarters laboratory (later, Alan Fletcher Research Station) at Sherwood, Brisbane. By the mid-1920s prickly pear had ravaged an area of some 65 million acres (26.3 million ha) in Australia, much of it prime agricultural land and most of it in Queensland. In May 1925 Mann received the historic shipment of the moth Cactoblastis cactorum that A. P. Dodd sent from Argentina. He bred the first generation of the insects and studied them and their progeny. The distribution of eggs to areas infested with prickly pear began the following year.

On 23 June 1926 at Rockdale, Sydney, Mann married, in a Church of Christ ceremony, Muriel Edith Dines, a stenographer. In 1929 he was appointed as a research entomologist and officer-in-charge of the Chinchilla Field Station, continuing its important role in the mass rearing and release of Cactoblastis cactorum. The prickly pear was under control by 1930 and the eradication program received international acclaim. Mentored by George Hardy, from the University of Queensland, Mann became an authority on the stiletto flies (Diptera: Therevidae). He produced three well-regarded publications, in which he described a new genus and some twenty-two new species. A genus, Johnmannia, and a species, Nanexila manni, were named after him.

Mann returned to the Sherwood laboratory in 1934 and spent the rest of his career there. When the Prickly-Pear Board was disbanded in 1939, he transferred as an entomologist to the biological section, lands development branch, Queensland Department of Public Lands, which took over the laboratory; Dodd was appointed as director. Among other responsibilities, Mann prepared in 1951 the first batches of myxomatosis virus for the control of rabbits in Queensland. The success of the campaign against prickly pear encouraged Dodd and his team to investigate the biological control of other noxious plants. Mann sought destructive insects in Mexico (1953–54) for lantana; in India (1957 and 1963) for Noogoora burr; and in the Americas (1958–59) for Harrisia cactus. His trip to Mexico ended when he became severely ill with amoebic dysentery.

In 1962 Mann succeeded Dodd as director, responsible for all research on chemical and biological control of weeds. His tenure marked ‘a period of enthusiasm, scientific resourcefulness, [and] official and primary industry recognition’ (Haseler 1985, 3). As well as speaking frequently at science conferences, he addressed public meetings and gave radio talks. He was a foundation (1975) and life member of the Weed Society of Queensland; a foundation member (1923), president (1940), and life member (1970) of the Entomological Society of Queensland; and a fellow of the Royal Entomological Society, United Kingdom (1964), and the Royal Zoological Society of New South Wales (1969).

 The publication in 1970 of Mann’s Cacti Naturalised in Australia and Their Control (1970) generated friction with Dodd, who believed that it understated the contributions of Mann’s colleagues to the prickly-pear program. After retiring that year, Mann compiled butterfly and other insect collections for schools. For his contribution to entomology, the biological control of prickly pear, and weed management, he was appointed MBE (1970) and awarded an honorary doctorate of agricultural science by the University of Queensland (1983).

Jack Mann was liked by his superiors, colleagues, and staff. Among the Christian Brethren community, he was a well-respected lay preacher. Upright bearing and a grey moustache gave him a distinguished appearance; from 1962 he walked with a limp as a result of a leg injury suffered in a car crash and used a stick. A passionate Christian and creationist, he gave talks on God as Creator and considered the relationship between cactus and Cactoblastis to be an example of divine purpose. He died on 27 June 1994 at Ipswich and was buried in Mount Gravatt lawn cemetery. His wife, their daughter, and one of their three sons survived him.