Defeating pests through nature

Hans Rudolf Herren has shown the whole world that agriculture does not need toxic chemicals. As Anna Birkenmeier in Zurich reports, the Swiss entomologist has been awarded the Right Livelihood Award for his work.


Hans Rudolf Herren grew up surrounded by nature, on a tobacco plantation in the Lower Valais run by his father. “Although I had always had a passion for nature, my interest in insects and how to control pests only came later,” said Herren, who was born in 1947. After pursuing studies in agriculture, he studied agronomy at the ETH Zurich. “This is where my interest for plants, animals and human health grew, which is why I decided to focus my studies on plant protection and organic pest control.” It was during his studies that Herren began to look at environmental problems, and in particular those caused by agricultural practices. “I wanted to develop sustainable solutions, and it soon became clear to me that I would not find my professional future in the plant industry in Switzerland.”

Using wasps to fight the mealybug

That it would end up being Africa was a coincidence – or good fortune, as Herren describes it. “I applied for a job at the International Institute of Tropical Agriculture in Nigeria and got it.” This is where he developed biological pest control for the cassava mealy bug. Cassava is the main staple crop for about 200 million Africans. When the tiny arthropod was accidentally introduced to central Africa in the 1970s, it started to destroy cassava crops. Hoping to head off an impending crisis, governments began widespread pesticide spraying programmes.

The breakthrough moment for Herren came when he identified a parasitic wasp in Paraguay that kills mealybugs. After having ensured that the wasp would not turn itself into a problem for African ecosystems, he began one of the biggest release campaigns of all times: Some 1.6 million wasps were unleashed against the mealybug between 1982 and 1993 in 24 countries, from Senegal to Angola. Wasps were spread over the fields from low-flying airplanes. “There is now a biological equilibrium between the mealybug and its natural enemies. No one speaks today of a mealybug problem.”

Higher yields without pesticides

Herren spent 15 years in Africa. “During this time it increasingly became clear to me that we can achieve sustainable, social and economic results when we work together with nature.” This realisation became a recurrent theme with his other work, including when he established the Biovision Foundation, which celebrated its 15th anniversary at the end of November. Through Biovision he is able to promote biological pest control and ecological agriculture in developing countries in Africa. “These days farmers are able to achieve higher yields with less toxic methods – an important step in the fight against hunger and poverty.”

Prize money changes the course

A project that Herren is currently working on with the Millennium Institute and Biovision is called ‘Changing Course in Global Agriculture’. “We want to show how the world can feed itself in a sustainable manner – even in 2050 when the world’s population hits 9 billion.” It is a matter of introducing sustainable agricultural practices based on the principle of organic farming – an agriculture practice, therefore, that produces enough nutritious food for everyone and is also climate friendly. “It is high time for our findings to be implemented and for consumers to rethink their practices – but that’s not an easy task,” says Herren.

The alternative Nobel Prize was awarded to him in recognition of his work. “We have a lot of work ahead of us and it’s time for the results to make their way to all levels: local, national, regional and global. This is why the renewed interest in our work – which the alternative Nobel Prize awoke – is very much welcome.” The prize money will be invested in “Changing Course in Global Agriculture”.

Photo credit: Biovision

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