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A bigger pest than the lovebugs? Korea ups warning against white moths.

Published: 11 Jul. 2025, 16:27

The fall webworm, known in Korea as the American white moth [NATIONAL INSTITUTE OF FOREST SCIENCE]

Could Korea soon be grappling with an insect as troublesome as the lovebug? Perhaps, as rising temperatures fuel the spread of the fall webworm — known locally as the American white moth.

The Korea Forest Service’s National Institute of Forest Science raised its alert level on Thursday for the pest from “attention” to “caution,” warning of mounting risks tied to climate change.

The American white moth, believed to have arrived from North America in the 1950s, has now spread across the Korean Peninsula, sparing only Jeju Island.

Its caterpillars appear two to three times a year, chewing through more than 200 types of plants.

Large outbreaks not only damage urban landscapes but also disrupt daily life. Contact with the larvae can trigger allergic reactions, such as rashes and stinging sensations.

The agency recently analyzed first-generation monitoring data from 1,600 broad-leaved trees across 32 fixed survey sites nationwide. It expects second-generation caterpillar damage to surpass previous years.

An insect generation refers to a full life cycle from egg to larva, pupa and finally adult, which then lays eggs to begin the cycle anew.

Based on this year’s first-generation data, the anticipated damage rate is 15.8 percent from the first round of larvae and 26.9 percent from the second round. These figures are higher than the 8.9 percent average recorded in the 2000s and the 6.7 percent in the 2010s.

The researchers attributed the spike to climate change. Higher temperatures in spring and fall have extended the insects' active seasons in spring and fall, leading to a greater likelihood of a third generation emerging.

Officials emphasized the need for intensified monitoring and control measures between mid-July and early August, when the second generation of larvae begins to hatch.

“This is the critical window to curb damage that typically peaks in summer and autumn,” the agency said.

Translated from the JoongAng Ilbo using generative AI and edited by Korea JoongAng Daily staff.
BY JANG GU-SEUL [[email protected]]