Biological weed control to relieve millions from Ambrosia allergies in Europe

Invasive alien species can affect ecosystem services and human well-being, yet quantitative assessments of their health impacts are rare, leading to underestimation of the benefits of management. We quantify the effects of the allergenic plant Ambrosia artemisiifolia (common ragweed) on public health in Europe and evaluate the potential impact of the accidentally introduced biological control agent, the leaf beetle Ophraella communa, on patient numbers and healthcare costs. Prior to O. communa establishment, an estimated 13.5 million persons in Europe suffered from Ambrosia-induced seasonal allergies, incurring approximately €7.4 billion in annual health-related costs. Field experiments and aerobiological monitoring indicate that O. communa substantially reduces ragweed pollen production and airborne concentrations. Projections suggest biological control will reduce the number of allergy patients by about 2.3 million (≈16.9%) and annual costs by approximately €1.1 billion. These conservative estimates imply that current economic cost assessments of invasive species likely underestimate true costs and the benefits of biological control.