How do I get rid of these centipede-like bugs?
My grandparents live on a farm in Lakefield, Minnesota. They have these centipede-like bugs in their house. They seem to be more prevalent at night, but are still out in the daytime. They live in a multilevel home and these bugs seem to be on every floor in every room except for the kitchen. They really seem to like the bathroom. My grandma picks many up every day, but she feels as though she can't stay ahead of it. She said she's never seen this type of bug before and she is a cleaning lady.
What are these things and what would be the best way to get rid of them and prevent them from coming back?
Minnehaha County South Dakota
These are millipedes, which are arthropods, but not insects. Millipedes feed on decaying organic matter and are helpful decomposers when outside. We do see them move indoors, generally by accident in the fall, but they do not take up residence.
The best defense against them is to make sure all doors, windows, and other entry points into the home are well-sealed. Outside, make sure that leaf litter is away from the foundation. They like the bathroom because that room is humid - using the exhaust fan while showering, and perhaps setting up a dehumidifier will make that area less hospitable for the millipedes.
This resource from UMN has additional information: http://www.extension.umn.edu/garden/insects/find/sowbugs-millipedes-centipedes/.
I spoke with my grandma and she said she put out four bug bombs at the beginning of August. She keeps a very clean house but says every time she kills one she feels like two more come. Is there any chemical way to to get rid of them?
The root cause of this is that they are coming in from outside. Bug bombs are not a good solution and pesticide sprays will only kill the millipedes that come into direct contact with the product. I really don't recommend bug bombs for anything, as they can be harmful to people and pets, and they don't penetrate into the areas where the pests are hiding. I know it is more effort, but finding their entry point and sealing that is the only way to stop them from getting inside.
The good news is that the millipedes are not dangerous to people - they really are considered a nuisance pest at best. Once we have a hard freeze, the problem will stop. Until then, continuing to vacuum or sweep up any that find their way inside is really the way to go.