Kubiaka Katsuyakamikiri Beetle Spreading in Hyogo: Protect Trees & Report Sightings
A destructive invasive insect, the glossy granulate ambrosia beetle (Cucurbitapion eleagni), is expanding its range within Hyogo Prefecture, Japan. First discovered in Miki City in 2022, the beetle’s impact has spread to four additional cities – Takasago, Kawanishi, Tamba, and Tamba-Sasayama – by 2025, affecting areas across eastern Hyogo. Prefectural officials are urging residents to assist in early detection efforts to prevent further spread.
The Threat to Local Flora
According to the Ministry of the Environment, the glossy granulate ambrosia beetle was initially identified in Aichi Prefecture in 2012 and has since established a presence in the Kansai region. The beetle lays its eggs on trees, and the larvae bore into the wood, ultimately causing the trees to die. This has resulted in reduced harvests in orchards and the widespread death of cherry trees, including entire groves.
Current Situation in Hyogo Prefecture
The Hyogo Prefectural Natural and Wildlife Symbiosis Division reports that the beetle was first found within the prefecture in Miki City in 2022. By September 30, 2025, 502 trees had been identified as affected, with approximately half requiring felling. The beetle’s adult form can fly up to 2 kilometers and can also spread via trains and vehicles, potentially reaching wider areas.
Identifying the Beetle and Reporting Sightings
Detecting the beetle’s presence involves looking for “frass” – a mixture of wood shavings and excrement resembling brown udon noodles – at the base and on the trunks of trees. While adult beetles are only visible between May and August, frass can be found year-round. Residents are asked to report any sightings of frass to the Hyogo Prefectural Natural and Wildlife Symbiosis Division via online form, email, or telephone.
Prefectural Response
In August of last year, Hyogo Prefecture established a task force, led by Governor Saito, to address the issue of this invasive species. A representative from the prefecture emphasized the importance of early detection, stating, “Early discovery is crucial to protecting cherry trees and other trees. While enjoying the blossoms, please also carefully observe the base of the trees and report any frass immediately.”
About the Glossy Granulate Ambrosia Beetle
The glossy granulate ambrosia beetle, originating in China and the Korean Peninsula, measures approximately 2 to 4 centimeters in length. It is characterized by its shiny black body and reddish-colored thorax. Designated as a specific invasive alien species in 2018 due to its potential for ecological damage, the beetle has few natural predators within Japan.
Frequently Asked Questions
When was the glossy granulate ambrosia beetle first confirmed in Hyogo Prefecture?
The beetle was first confirmed in Hyogo Prefecture in 2022 in Miki City.
What does the frass look like?
The frass looks like a mixture of wood shavings and excrement, resembling brown udon noodles.
How can residents report sightings?
Residents can report sightings via an online form, email, or telephone to the Hyogo Prefectural Natural and Wildlife Symbiosis Division.
Given the potential for this invasive beetle to further impact Hyogo Prefecture’s trees, what role do you think local communities can play in protecting their natural environment?