Pakistan, Jan. 9 -- The hugely popular "snow monsters" that inhabit the mountains of Zao are on the brink of extinction and it could spell disaster for the tourism industry in that part of Yamagata Prefecture, in northern Japan.

For years, "snow monsters" - unique formations that occur when a fine mist of water from clouds over the warmer Sea of Japan coats evergreen trees and then freezes - have been one of the region's main attractions. Now, however, the coniferous trees have become infested with bark beetles and caterpillars that develop into a moth of the Gelechiidae family.

The 3mm-long palmerworm caterpillar was first identified on trees in the region in 2013, leading to an infestation of beetles on trees that were already damaged...