In 2013, Ophraella communa landed in Europe. Ophraella communa is the official name of the ragweed leaf beetle. It is said that it got there by accident from its native lands Canada, United States, and Mexico. It got in Southern Asia at the same time, presumably by accident too. As of 2014, in Europe, it has been found in southern Switzerland and northern Italy.
The beetle feeds with leaves and flowers of sunflowers, rough cockleburs, and common ragweed aka Ambrosia artemisiifolia. For the sunflowers, the insect can be detrimental. Also, since the common ragweed is considered invasive in Europe and Asia, the ragweed beetle could be considered a biological control agent too.
The problem with Ambrosia artemisiifolia is that its wind-dispersed pollen is highly allergenic and dangerous for people suffering from hay fever during its bloom period. In North America blooming lasts from July to October with the highest risk time between August 7 to August 13. Unlike intentional releases of biological control agents, Ophraella communa didn’t go to the usual process of risk assessment.
This is what determined Sandro Steinbach is an expert in the Agricultural and Resource Economics Department at the University of Connecticut to engage in research and find whether Ophraella communa is more of a harmful beetle or a beneficial biological control agent.
The outcomes of the study on the ragweed leaf beetle
The results of the study are impressive. Opharella communa can be a life savior for people suffering from hay fever with the help of the little bug. The common ragweed attacked by Ophraella communa can get completely defoliated. 13.5 million Europeans suffer from hay fever while allergies induce 7 billion Euros in economic losses each year.
“Our conservative estimates indicate that biological control of Ambrosia artemisiifolia by Opharella communa will reduce the number of patients by approximately 2.3 million and the health costs by Euro 1.1 billion per year,” said Steinbach. Previously, Russia and China used Zygogramma suturalis for ragweed control, and results were considered to be positive.
Going back to the possibility of the beetle being harmful to sunflower cultures, study co-first author Urs Schaffner said that “However, field tests in China and Europe could not confirm this finding.” It might be so but there are other risks to be considered.
If scientists and governments decide to decimate Ambrosia artemisiifolia one thing shouldn’t be forgotten: this plant has a special power. It remediates soil pollution by removing heavy metals. It can clear contaminated soil from lead. So, maybe the economical losses aren’t that important after all.