The leaf beetle Ophraella communa can significantly reduce pollen and that may mean a more cost-effective way to reduce allergies and their health care costs using science, while still appealing to activists that otherwise would oppose it.

Ambrosia artemisiifolia, ragweed, causes sneezing and itchy eyes in those with an allergy and aggravates conditions such as asthma and eczema.

Prior to the 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. Just this once, an invasive species did some good. Because it stopped another invasive species, common ragweed. Field studies in Italy have proved that the leaf beetle reduced 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.

Leaf beetle Ophraella communa. Credit: Professor Heinz Müller-Schärer

In the past, invasive species were introduced because they were politically palatable. In the home state of Science 2.0, California, yards are overrun with horrid-smelling trees Pyrus calleryana (Callery Pear) trees because environmentalists convinced their political allies that they could grow anywhere with little water. So government began offering rebates to homebuilders and now yards are infested with hard shoots sprouting that can't be killed without glyphosate. The new study instead calls on future assessments of the economic impacts of Invasive Alien Species to more thoroughly consider costs related to human health, something the U.S. should do before letting politicians mandate alternatives to science as well. 

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.