<Anchor> This

is a glass-alarmed cow living in a mountainous area in Gangwon-do, Korea. However, this sky cow began to appear in the metropolitan and southern regions, killing trees in the city. Analyzing these suddenly increased sky cows, it was an individual from China, not Gangwon-do.

This is reporter Song In-ho.

<Reporter> This

is Samrak Ecological Park, a representative willow community in Busan.

The trees are dying, but when I split the perforated tree, I dream of something inside.

It is a glass-like sky place.

[Lee Seung-Hyun/Seoul National University Insect System Classification Researcher: There is one larva that started from the egg. This is a large chrysalis before it becomes a pupa before becoming an adult. If you eat this inside, the tree will die.]

Adult mating or laying eggs are found throughout the tree.

It is a willow tree that has been damaged by a glass-eyed cow.

As you can see, the tree trunks are dug up and dying.

In this way, Yuri Alaska Cattle is attacking indiscriminately without covering young trees.

The damage is concentrated not only in Busan, but also in southern areas such as Ulsan and Jeonju, as well as in metropolitan areas such as Incheon and Seoul.

[Kim Hyun-Woo/Director of the Nakdong River Management Headquarters in Busan City: The mass incidence has been confirmed since 2015. Since there is no countermeasure, we are cutting down willow trees.]

Why did the glass alley cattle that lived in the mountainous regions of Gangwon-do rapidly multiply to the south of the metropolitan area?

Researchers at Seoul National University solved the question after analyzing the gene over six years.

It was confirmed that the genes of the populations in the metropolitan area and the southern regions were significantly different from those in the mountains of Gangwon-do.

It means that it came from abroad.

[Lee Seung-Hyun/Seoul National University Insect System Classification Researcher: It is thought that the glass-algae globules have flowed from China to port cities such as Incheon and Busan. It is spreading rapidly around those cities.] The

damage can be even greater because there is no decent control.

[Lee Seung-Hwan/Professor of Insect System Classification, Seoul National University: There is a problem that the destructive power increases when an organism meets a foreign group and a native group and becomes a group. The possibility of doing more harm to more plants.] In

North America and Europe, it has already caused enormous forest damage.

Countermeasures are urgent as it has been confirmed that they have flowed from China.

(Video coverage: Hojun Choi, VJ: Oh Se-gwan, Video editing: Ha Sung-won)