The World Food Prize Foundation

1995: Herren

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Dr. Hans Rudolf Herren 


Dr. Hans Rudolf Herren, recipient of the 1995 World Food Prize, was only 31 years old when he took a new job in Africa and landed right in the middle of an unprecedented crisis: an insect, the cassava mealybug, was devastating the continent’s staple crops, and widespread hunger was emerging as a real possibility. Within ten years, Dr. Herren had almost single-handedly developed a chemical-free biological control for the mealybug, eliminated the threat to cassava production, averted disastrous famine, and saved upward of 20 million lives.

Full Biography

Born in Switzerland in 1947, Dr. Herren arrived at the International Institute of Tropical Agricultural in Nigeria in 1979 after receiving his Ph.D. from the Federal Institute of Technology in Switzerland and completing post-doctoral research in ecology at Berkeley. Six years earlier, the tiny arthropod Phenacoccus manihoti, or the mealybug, had been accidentally introduced to central Africa from its native South America. Lacking natural predators, the species caused an immediate crisis by attacking the cassava – a hardy plant grown by subsistence farmers across Africa and providing up to 50 percent of a day’s caloric nutrition to 200 million people – and ruining as much as four-fifths of the crop in some areas. To head off an impending crisis, governments had begun widespread pesticide spraying programs.

Dr. Herren proposed that, instead of using expensive chemicals that could harm African ecosystems and contaminate its food supplies, governments and farmers could find a natural predator to the mealybug. Similar projects had succeeded elsewhere for over a century, but nobody had tried on the scale Dr. Herren was proposing, a swath reaching from Senegal to Angola in the west and across the continent to the eastern island of Madagascar. It would require enormous amounts of time, money, and effort; Dr. Herren was the sole member of the biological control program at IITA. 

From 1980 to 1984, Dr. Herren researched his proposal. He identified a Paraguayan wasp, E. lopezi, that kills the mealybug but does not threaten other organisms. Having ensured the wasp’s long-term suitability to African ecosystems, he outlined a plan to spread E. lopezi populations through ground releases coordinated with drops from airplanes. To support the project, he organized $20 million over 12 years from international institutions and governments. By 1986, Dr. Herren was releasing almost 2000 wasps per second across areas affected by the mealybug.

Results followed quickly: within five months of the project’s initiation, one wasp population had spread over 120 miles. By 1993, mealybug numbers had stabilized to controllable levels in 30 countries, and its relationship with E. lopezi had reached ecological equilibrium as well. Africa’s cassava reserves – the only hope for feeding the continent’s people in famine situations – were saved.

In the process, Dr. Herren built the biological control program at IITA into a major center staffed by over 20 scientists, who in turn assist hundreds of researchers, educators, technicians, and farmers in biological control programs worldwide. Dr. Herren himself trained over 850 experts from 30 countries in biological and integrated control techniques.

Following his tenure at IITA, Dr. Herren directed the International Centre of Insect Physiology and Ecology (ICIPE) in Nairobi, Kenya from 1994 to 2005, and has since been named President of the Millennium Foundation in Arlington, Virginia.

With the cash award of the World Food Prize, Dr. Herren in 1998 established BioVision, a private foundation that funds and promotes science-led sustainable development projects in sub-Saharan Africa, and continues to serve as the foundation’s chairman. Additionally, he is co-chair of the International Assessment of Agricultural Knowledge, Science, and Technology and president of the International Association of the Plant Protection Sciences. He remains a leading proponent for the development of biological controls and other ecologically sound management methods throughout Africa and the tropics. His interests and present activities cover areas from sustainable development – including plant, animal, and human health, conservation, and poverty – to the development and dissemination of system dynamic simulation models in support of informed policy formulation.

Dr. Hans R. Herren received the 1995 Kilby Award, the 2002 Brandenberger Award for his dedication to improving the welfare of mankind, and the 2003 Tyler Prize for Environmental Achievement. Dr. Norman Borlaug, Peace Prize Laureate and founder of the World Food Prize, has said that “to improve and protect the world’s food supply is both one of the highest and most basic of callings. Dr. Herren has answered that call in an exemplary manner.”

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