Pine wilt disease detected in Gangdong-gu as Seoul moves to contain spread

The Seoul Metropolitan Government said Monday it has activated an emergency response system with the Korea Forest Service and other agencies after a pine tree infected with pine wilt disease was confirmed in Gangdong-gu, and that it will make every effort to prevent the disease from spreading.

The infected tree was one of nine pines submitted for laboratory testing during a routine surveillance inspection in Gangdong-gu. It was confirmed positive through a secondary diagnosis on Monday.

Pine wilt disease is caused by a microscopic nematode roughly 1 millimeter in length. The parasite lives inside its insect vectors — primarily the Japanese pine sawyer beetle, which targets pine trees, and the white-spotted sawyer, which mainly attacks Korean white pine — and enters host trees through feeding wounds when the beetles gnaw on new shoots.

The city has managed pine wilt disease under a three-pronged response framework centered on strengthening prevention-focused surveillance, containing spread from confirmed sites, and preventing human-assisted transmission. Given the continued occurrence of the disease in neighboring areas including Namyangju and Hanam, however, the city said it views this latest case with serious concern and plans to work with the Korea Forest Service and district offices to establish a containment line from the outset and actively block any further spread.

The newly confirmed site is about 3.7 kilometers from existing outbreak locations in Sampae-dong, Namyangju and Chooil-dong, Hanam. Seoul plans to conduct an epidemiological investigation into the cause of the outbreak and the route of infection.

The city is currently carrying out a detailed surveillance sweep within a 5-kilometer radius of the site to quickly determine whether additional infected trees are present, while also pursuing an epidemiological investigation to identify newly infected trees early and analyze the cause of the outbreak. It also plans to complete a control design promptly and mobilize all available administrative capacity and pest-control resources to contain the spread in and around the affected area as quickly as possible.

In addition, the city will make active use of advanced surveillance techniques and work with relevant agencies to improve early detection of infected trees through drone and ground-based patrols. It plans to review a range of measures — including improvements to pesticides and control methods — to build a more efficient pest-management system that maximizes control effectiveness.

Under the Special Act on Pine Wilt Disease Control, the city will intensify enforcement against the unauthorized movement of pine trees without a disease-free certificate, as well as the illegal transport of potentially infected pines or firewood. It will respond strictly in accordance with relevant laws to any illegal activity that contributes to the spread of pine wilt disease.

"We will do our utmost to detect infected trees early and contain the spread by working closely with related agencies from the very start," said Kim Yeong-hwan, director of the Seoul Metropolitan Government's Garden City Bureau. "We also ask citizens to immediately report any abnormal symptoms — such as pine trees suddenly withering and dying — and to refrain from moving pine trees or firewood without authorization."