Woman with allergy from ragweed

Prior to the accidental arrival of the leaf beetle in 2013, some 13.5 million people suffered from ragweed-induced allergies in Europe, causing economic costs of approximately Euro 7.4 billion annually.

CABI has led a team of scientists on new research which reveals that a humble bug can help relieve more than 2 million sufferers of allergies in Europe while also saving more than Euro 1 billion in health costs.

Dr Urs Schaffner, lead author of the study published in Nature Communications, says the leaf beetle Ophraella communa can significantly reduce pollen – which causes a range of symptoms from sneezing to itchy eyes and aggravates conditions such as asthma and eczema – from common ragweed (Ambrosia artemisiifolia).

The interdisciplinary study – the first to quantify the economic benefits of biological control in Europe – also argues that the costs inflicted by invasive species in Europe are ‘most probably seriously underestimated’. The team of scientists from institutions including the University of Fribourg and ETH Zurich, Switzerland, the University of Worcester, UK, and Leiden University, NL, suggest countries in the Balkan Peninsula – such as Bulgaria, Romania and Serbia – will benefit most from the leaf beetle as a biological control.

Prior to the accidental arrival of the leaf beetle in 2013, some 13.5 million people suffered from ragweed-induced allergies in Europe, causing economic costs of approximately Euro 7.4 billion annually. In Europe, common ragweed is considered invasive in more than 30 countries and its spread and impact, the scientists say, is likely to increase with rising temperatures caused by climate change.

Leaf beetle

The leaf beetle ‘attacks’ the common ragweed by eating it before it has a chance to flower and release pollen – photo: Heinz Müller-Schärer

Field studies in Italy have proved that the leaf beetle can reduce ragweed pollen by 82 percent. In the Milan area, where the beetle was first detected, up to 100 percent of ragweed plants were attacked and the damage caused was enough to prevent flowering that causes pollen to be released.

Dr Schaffner, who is based at CABI’s centre in Switzerland, said, “Our study provides evidence that the impacts of common ragweed on human health and the economy are so far highly underestimated, but that biological control by Ophraella communa might mitigate these impacts in parts of Europe. “We propose that future assessments of the economic impacts of Invasive Alien Species (IAS) should more thoroughly consider costs related to human health.” The scientists drew upon information from the European Pollen Monitoring Programme before mapping seasonal total ragweed pollen integrals in Europe during 2004 and 2012 – prior to the introduction of the leaf beetle. They then interpolated data from 296 pollen monitoring sites across Europe.

To validate the estimated number of patients suffering from ragweed pollen allergy, the researchers compared their European-wide assessment with detailed healthcare data from the Rhône-Alpes region in southeastern France. They then weighted the treatment and lost work time cost at the country level using purchasing power parity – adjusted health expenditures per capita for 2015 – to determine the overall economic costs of healthcare to treat the symptoms and other effects of ragweed pollen. Professor Heinz Müller-Schärer, of the University of Fribourg, said, “We were not sure as first whether the leaf beetle was useful or harmful. Laboratory tests had shown that it was possible that it was harmful to sunflowers. However, field tests in China and Europe could not confirm this finding.” Dr Schaffner, Professor Müller-Schärer and the other authors conclude that accurate information of policy and management about the impact of IAS on human health and the potential savings – due to the implementation of mitigation measures – is essential to ensure that reasonable resources are invested and actions coordinated in IAS management.  

Notes to editors Full paper reference Schaffner, U., Steinbach, S., Sun, Y., Skjøth, C., de Weger, L.A., Lommen, S.T., Augustinus, B.A., Bonini, M., Karrer, G., Šikoparija, B., Thibaudon, M and Müller-Schärer, H., ‘Biological weed control to relieve millions of allergy sufferers in Europe’ Nature Communications, 2020, DOI: 10.1038/s41467-020-15586-1 The paper is available to read here: Photos of common ragweed (Ambrosia artemisiifolia), the leaf beetle Ophraella communa, Dr Urs Schaffner and Professor Heinz Müller-Schärer are available to download on Dropbox. See also video on YouTube.

Media enquiries Wayne Coles, Communications Manager, CABI, email: Tel: +44 (0)1491 829395 Dr Urs Schaffner, Head of Ecosystems Management, CABI, email: Tel: +41 (0)79286 4537 Professor Heinz Müller-Schärer, University of Fribourg, email: Tel: +41 (0)79 7873571

About CABI CABI is an international not-for-profit organization that improves people’s lives by providing information and applying scientific expertise to solve problems in agriculture and the environment. Through knowledge sharing and science, CABI helps address issues of global concern such as improving global food security and safeguarding the environment. We do this by helping farmers grow more and lose less of what they produce, combating threats to agriculture and the environment from pests and diseases, protecting biodiversity from invasive species, and improving access to agricultural and environmental scientific knowledge. Our 49 member countries guide and influence our core areas of work, which include development and research projects, scientific publishing and microbial services.

About University of Fribourg The University of Fribourg encompasses five faculties where people study, teach and research. These are Arts and Humanities, Science and Medicine, Management, Economics and Social Sciences, Law and Theology. The approximately 10,000 students in the Bachelor, Masters and PhD programs receive first-class personal support from over 800 professors, lecturers and research assistants. As the only bilingual university in Switzerland, the University of Fribourg offers a wide range of courses of study in French, German or both. The members of the University community come from 110 countries and make Fribourg with its 40,000 inhabitants a university town “par excellence”.