Who are we?

The International Ragweed Society (IRS) is a non-profit association based in Nyon, Switzerland, established in 2009 under Articles 60 ff. of the Swiss Civil Code for an indefinite period. The Society brings together researchers, physicians, aerobiologists, agronomists, ecologists, public-health professionals, policy makers and other stakeholders who share a common interest in ragweed (Ambrosia L.) and its impacts on health, agriculture and the environment.

Our core aim is to advance and disseminate knowledge about ragweed, to support high-quality research, and to translate scientific evidence into practical tools for management and prevention. To this end, IRS promotes collaboration across disciplines and countries, facilitates research and education, and fosters the development of technical solutions, public information, best practices and legal frameworks dealing with ragweed and its direct and indirect effects.

IRS serves as an international platform connecting individuals, associations, scientific societies and institutions active in the field. The Society is responsible for electing the bodies that organize the International Ragweed Conferences and for encouraging cooperation with related fields, especially those linked to environmental and health issues.

Beyond conferences, we aim to organize courses and educational programs, coordinating and backing projects, proposing quality standards and quality control procedures, stimulating young researchers, developing control actions, and maintaining databases related to ragweed.

Founded by its constituting Assembly on 2 October 2009, the International Ragweed Society continues to evolve as a global reference point for science-based action managing the impacts of ragweed.

VISION

To be the leading global platform advancing studies on ragweed (Ambrosia spp.) through evidence‑based understanding, monitoring, and sustainable management of ragweed through integrated One Health solutions.

MISSION

The International Ragweed Society (IRS) advances multidisciplinary research and knowledge on ragweed and its direct and indirect impacts on health, agriculture, and the environment. Guided by the One Health approach, IRS:

Promotes collaboration among weed scientists, health authorities, aerobiologists, policymakers, and stakeholders to specifically improve monitoring, risk assessment, and biological control of ragweed while respecting ecosystem balance.
Develops and shares scientific evidence, educational programs, and technical tools to support effective, proportionate, and law‑informed ragweed management and public health responses, while emphasizing the necessity of integrating ragweed biocontrol as a scientifically grounded component of these strategies.
Creates an open, international forum for individuals and institutions interested in ragweed, including the organization of International Ragweed Conferences and support for young researchers.
Integrates observation, measurement, understanding, and management of ragweed into coordinated global actions that reduce the burden of ragweed while contributing to planetary and One Health wellbeing.

Ragweed (Ambroisia spp.) has invaded different parts of the world and its spread and impact are likely to increase with the changing climate. The North American native Ambrosia artemisiifolia L. has raised awareness as the main cause of allergy and pollen asthma in North America and Central Europe, and as a major agricultural weed in spring-sown crops.

Beyond its biological invasiveness, ragweed represents a growing global socio-economic burden due to rising healthcare costs, productivity losses and increasing expenditures for land and infrastructure management.

Ragweed (Ambrosia L.) is at the core of the Society’s concern because of its profound impact on human health, agriculture and ecosystems. The main cause of late-summer pollinosis and pollen-induced asthma in North America and increasingly in Eastern, Central and parts of Southern Europe is ragweed pollen, produced in great quantities by several Ambrosia species, of which common ragweed (A. artemisiifolia) is the most widespread. Climate change acts as a powerful amplifier of these impacts by extending pollen seasons, increasing pollen allergenicity through elevated CO₂ concentrations, and facilitating the spread of ragweed into new regions previously unsuitable for its establishment.As these allergenic species continue to expand beyond their native range, they are now recorded throughout Europe, temperate and tropical Asia, Africa, South America, Australasia and Pacific islands, turning ragweed into a truly global invasive allergenic weed and amplifying its potential to disrupt crop production and natural habitats. In response, the International Ragweed Society seeks to be the leading global platform uniting ragweed science and One Health, ensuring that Ambrosia is responsibly managed within ecosystems to protect human, animal and environmental health.

Ragweed is a monoecious, highly invasive annual plant whose male flower heads, borne at the top of the plant, release vast amounts of wind-borne pollen from August to September, while female flowers below form large numbers of seeds with very high germination capacity. This biological profile gives ragweed a greater spread potential than most native annual broadleaf and grass weed species and makes it difficult to control once established, with dense infestations reducing yields, outcompeting native vegetation and altering ecosystem processes. By displacing native plant communities, ragweed contributes to biodiversity loss and undermines ecosystem services essential for resilient agricultural and natural landscapes. Effective management therefore requires not only continued scientific research, impact assessment and monitoring to underpin evidence-based control strategies, but also coordinated action by farmers, managers of natural areas, road and railway authorities, construction and gravel industries and local communities, with systematic removal of even small foci of plants to reduce seed production and slow further spread.

Despite its transboundary spread and global consequences, ragweed management remains fragmented and largely local, highlighting a critical gap in international coordination, shared strategies and policy integration. Aligned with its mission, the International Ragweed Society promotes interdisciplinary research, education and collaboration across environmental, agricultural, medical and health-related sciences, and serves as a global platform connecting researchers, institutions, practitioners and policymakers to promote innovative, scientifically grounded strategies for sustainable ragweed management and control.

Further information

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