Ash-killing emerald borer reaches the EU in Hungary and Slovakia
Authorities say the invasive beetle, blamed for tens of millions of damaged ash trees in North America, has been found inside the EU.
By Georgia Hale · Staff Writer
3 min read
An invasive beetle notorious for attacking ash trees has been detected in the European Union for the first time, with authorities in Slovakia and Hungary confirming finds near their eastern borders.
Slovakia’s Agricultural Central Control and Testing Institute, known as UKSUP, said 18 emerald ash borers were found this month in the Streda nad Bodrogom district in the country’s east.
Hungary’s food safety office, NEBIH, said two adult emerald ash borers were discovered in June in a trap in the Beregsurany forest, close to Hungary’s border with Ukraine.
The insect, which originated in Asia, can reach about half an inch in length as an adult. NEBIH described it as “one of the most serious pests affecting ash trees” and said it has already caused major ash tree deaths in North America and Eastern Europe.
Hungary steps up checks
Hungarian authorities have ordered additional traps and tighter monitoring to gauge how far the beetle may have spread, according to NEBIH.
The agency has also asked members of the public to report ash trees showing suspicious symptoms.
The discovery has already reached Hungary’s political agenda. Hungary has asked for the beetle’s presence to be discussed at the next meeting of EU agriculture ministers.
Hungarian Agriculture Minister Szabolcs Bona told the farm news website Agroinform.hu that officials understand the seriousness of the find.
“We are aware of the gravity of the situation and are doing everything possible to prevent this pest from becoming permanently established in Hungary or turning into a plant health issue for the whole European Union,” Bona said.
A costly invader in North America
The emerald ash borer has a long record of destruction across North America. The U.S. Department of Agriculture says the pest has killed or damaged tens of millions of ash trees and has been detected in 38 states and Washington, D.C.
According to the USDA, the beetle was first detected in North America in 2002 in southeast Michigan.
The agency says the insect is well adapted to the region’s conditions. “The beetle is well-suited to our climate, is a good flyer, and spreads naturally,” the USDA says.
Minnesota first recorded the pest in 2009 and later began using certain wasp species to target it, according to CBS News Minnesota. Those wasps attack the emerald ash borer at different points in its life cycle without harming other species, the report said.
A 2025 study also found that some fungi in Minnesota can kill the invasive beetle, CBS News Minnesota reported.
The beetle has continued to appear in new places in the United States. CBS News Colorado reported that it was found in Denver for the first time last summer, and CBS News Minnesota reported that it reached North Dakota in 2024.
Many European countries have emergency plans prepared for a possible detection of the emerald ash borer, according to authorities cited in the reports. The new confirmations in Hungary and Slovakia put those plans under fresh pressure as officials try to keep the pest from settling in across the bloc.
This story draws on original reporting from CBS News.