It is reported that the nematode infiltrates into the tree, cuts the passage of water and nutrients and excretes toxin, thus killing the tree in the end. The disease has so far swept 80 regions of south Korea since it first broke out in Pusan in 1988.

Pine trees that were blighted have increased each year, reaching 132,000 in 2010 and 506,000 in 2012.

This year, too, the disease was reported in regions including Kaphyong, Yangju and Ansong in Kyonggi Province with at least 300,000 pine trees being blighted and the damage rapidly expanding.