Bed bugs can climb up a wall, across a ceiling and drop on to a person.
To hinder this event, one can make a barrier for their wall. This is easy and inexpensive. The harder it is for bed bugs to bite you, the less they produce eggs, and so that makes it easier to at least hinder their growth, to give time and effort to exterminate them.
Logic dictates that it is best to put the wall barrier along the lower part of the wall, to discourage bed bugs from climbing up further into electric sockets, light switches, light fixtures, etc. Now, just with a wall barrier alone, they can still get to the wall via the door frame or closet door, etc. So multiple wall barriers are better than just one, such as putting an additional wall barrier on the wall around any door frame. This may sound tedious, but once it’s done once, it won’t have to be done again for a very long time (unless you get liquid on the sticky-side of the tape, or pull it down accidentally).
2. Put light-colored masking tape on the wall horizontally, around the perimeter of the room
2a. The masking tape is to protect your paint
2b. You may have to put two lines of masking tape, side-by-side, if the shipping tape is wider than the masking tape
3. Put smooth plastic shipping tape over the masking tape.
4. Get a bowl and put some talcum powder in it
5. Get a cotton ball, tissue, makeup foundation applicator, or small duster and dip it into the talcum powder
6. Apply a thin layer of talcum powder on the shipping tape on the ceiling. You can use a dust mask and goggles to prevent talcum powder from being inhaled or getting into your eyes if you wish.
Talcum powder makes it additionally harder for bed bugs to crawl on smooth surfaces. Note: bed bugs prefer dark colors and black over white. Therefore, using a light-colored masking tape is better than the dark blue or other color versions.