Should these tags be synonyms? If not, shouldn't we provide guidance on their differences?
pest and pest-control should be combined. I would combine them into pest-control both because that is the more frequently used tag and also because that emphasizes the DIY part - control of the pests.
While termites are the most extreme example, there are plenty of other pests that can damage a home, either directly (like termites) or indirectly (smells or unsafe conditions). Cockroaches, wasps, flies, rats, etc. are all problems that can have DIY solutions, though in some cases the best answer, as with some other types of questions, will be "call a professional".
- Questions you would typically ask a home contractor - If you have to call a professional pest control company, what should you tell them?
- Which tools, materials, and best practices for home improvement task - 100%
- Identifying the source or cause of a problem within your home - Where are the pest coming from? Why are they in your house instead of staying outside?
- National building codes (of any country) - Sometimes relevant, particularly for renters trying to get a landlord to fix a pest problem that is partially due to code violations.
- Installation, maintenance, and repair of major appliances - Depending on where the pests are hiding, this can be relevant.
- Carpentry and woodworking - very relevant when it comes to termites, carpenter ants, etc. but also for figuring out how to block entrance of pests.
Many of the details indeed fit with the general DIY question guidance:
These tags should be burninated and relevant questions closed; pest control may make your home more enjoyable, but it doesn't improve the home, itself, anymore than furnishings improve the home. As the help center states, DIY.SE is the site for the following kinds of questions:
- Questions you would typically ask a home contractor.
- Which tools, materials, and best practices for home improvement task.
- Identifying the source or cause of a problem within your home.
- National building codes (of any country).
- Installation, maintenance, and repair of major appliances.
- Carpentry and woodworking.
None of these are topics that cover things like how to get rid of roaches, squirrels, rats, mice, cats, fleas, bedbugs, etc.
The one exception would be termites, because they directly cause damage to structural members of wooden houses.