In Muan County's Samhyang-eup, 12 pine trees have been confirmed infected with the pine wood nematode, raising alarms for the local forest.
Once aiming for a designation as a 'clean area' with no infections, Muan County has seen a notable increase in infected trees. This year, 46 out of 274 trees tested for the nematode were confirmed infected.
Notably, the 12 recently identified trees are part of the 46 confirmed cases, indicating a need for proactive measures to prevent further spread rather than dismissing it as isolated incidents.
According to Muan County's data on the occurrence and control of the nematode, the disease was first detected in October 2015 in the Wangsan-ri area of Samhyang-eup.
Over the past five years, the trend shows that only one tree was confirmed infected from May 2021 to April 2022, and there were no infections from May 2022 to April 2023.
However, from May 2023 to April 2024, seven trees were reported infected, followed by a drop to one tree from May 2024 to May 2025, and then a sharp increase to 34 trees from June 2025 to May 2026.
The situation this year is also concerning.
Muan County has tested 274 pine trees for nematode infection, with 46 confirmed cases, including the 12 recently identified in Samhyang-eup.
The recent surge in infections is particularly noteworthy given that Muan County had previously aimed for a 'clean area' designation.
After a single infected tree was found in March 2022 in Namseong-ri, Cheonggye-myeon, no further infections were reported, prompting plans for a clean area transition. However, in May 2023, another infected tree was confirmed in Sinhak-ri, Muan-eup, halting those plans.
In 2024, the nematode was also detected in the border area between Muan and Hampyeong, leading local authorities, including Jeonnam Province, Muan County, and Hampyeong County, to hold a pest control meeting. They initiated measures such as complete tree removal, preventive injections, and drone inspections to curb the spread.
The management area has also expanded. The area designated for prohibiting the removal of pine trees in Muan, which was 12,763 hectares in December last year, has increased to 21,204 hectares as of March this year due to additional infections. This marks a 66% increase in just three months.
While the expansion of the removal prohibition area does not directly correlate with the increase in infected trees, it highlights the need for more thorough inspections and control measures as the area requiring management grows.
Currently, Muan County operates an eight-member pest monitoring team. Given the recent surge in infections, there are calls to reassess the monitoring personnel, their assigned areas, and the pest control system.
The pine wood nematode spreads when it is carried to healthy pine trees by pests such as the pine weevil and the northern pine weevil. Infected trees are likely to die, making early detection and removal of infected trees, along with blocking the movement of the pests, crucial for control efforts.
Local resident Kim Seok-gu, 57, stated, "We shouldn't take the number of infected trees lightly. With 12 trees confirmed in Samhyang-eup, we need to conduct thorough inspections of the surrounding forests to prevent further spread."
While the 12 infected trees may not seem like a large number, the recent confirmation of 34 trees in the control year and 46 this year cannot be overlooked, especially considering that the area once reported zero infections annually.
The challenge for Muan County's nematode control efforts will be whether proactive measures, such as detailed inspections around the infection sites, preventive injections, and pest control, can effectively break the cycle of further spread.
* This article has been translated by AI.
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