After entering the old house, there will be many large bugs in the area, some of them will just be sitting on walls. All you have to do is walk up to one and stab them. It should die in one hit. Other insect enemies do not count toward this achievement / trophy.
Here is a video guide with English commentary!
Here is a playlist of guides for this game!
https://www.youtube.com/playlist?list=PL-HeW6XkKdUKUtj7CV_kW...