Korea turns to eco-friendly pesticides to combat surge of lovebugs

Lovebug larvae / Courtesy of National Institute of Forest Science

Korean forest researchers are accelerating field trials of eco-friendly pesticides to combat a massive surge of Plecia longiforceps — commonly known as lovebugs — that has swarmed mountains and residential areas near the capital.

The National Institute of Forest Science said Monday that it is conducting outdoor trials using three types of organic pest-control agents on Mount Baeknyeon in Seoul and Mount Gyeyang in neighboring Incheon. The move comes after the insects mass-reproduced in these areas, causing widespread discomfort for hikers and residents and emerging as a distinct local nuisance.

The lovebugs, which are a species of march fly, earn their nickname from their behavior of flying in mating pairs. While harmless to humans and ecologically beneficial as decomposers, their sheer numbers in urban forests and apartment complexes have triggered public complaints.

Looking for a sustainable solution, the institute's forest pest research division recently tested two entomopathogenic fungal agents and a plant-extract based pesticide in a lab setting. After the eco-friendly mixtures demonstrated high mortality rates against the insects, researchers moved quickly to initiate the outdoor trials.

In coordination with local municipal offices in Seoul and Incheon, scientists treated designated test plots near the peaks of Mount Gyeyang in April and Mount Baeknyeon in May. Researchers plan to monitor these sites continuously to analyze the cumulative emergence rates of the flies, comparing treated areas against untreated control groups to verify the pesticides' real-world efficacy.

Even after the current adult population fades, the institute plans to target the next generation, applying the organic treatments to newly hatched larvae later this year.

"Outdoor field experiments can present variables due to weather and environmental conditions that differ from a controlled laboratory," said Park Yong-hwan, a researcher involved in the study. "However, based on these results, we intend to establish optimal timing and application methods, working closely with local governments to minimize public inconvenience."

This article was published with the assistance of generative AI and edited by The Korea Times.