The same active ingredient comes in different formulations - dust, liquid, bait, granular, aerosol, and foam. Each has specific advantages. Using the wrong formulation is one of the most common DIY pest control mistakes. This guide tells you which formulation to use for each situation.
All pest control situations. The formulation you choose is as important as the active ingredient. Boric acid dust in wall voids works brilliantly; boric acid dust on a kitchen counter is useless and messy.
See individual active ingredient pages for specific product recommendations in each formulation type.
Safety varies by formulation even for the same active ingredient. Dusts pose inhalation risk. Liquids pose skin absorption and drift risk. Baits are generally the safest because the active ingredient is contained in a matrix. Aerosols pose inhalation risk in enclosed spaces.
When to use each formulation:
| Formulation | Best For | Avoid When | Key Advantage |
|---|---|---|---|
| Dust (powder) | Wall voids, cracks, crevices, attics, electrical outlets | Exposed surfaces, damp areas, outdoors (blows away) | Lasts indefinitely in dry voids; reaches hidden pests |
| Liquid concentrate | Perimeter treatments, crack and crevice spray, lawn/garden | Inside wall voids, near food prep without proper technique | Most versatile; adjustable dilution rates; residual barrier |
| Gel/paste bait | Cockroaches, ants (indoor colony elimination) | Outdoor use (dries out); situations needing instant knockdown | Colony elimination via transfer; lowest exposure risk |
| Granular bait | Ant mounds, outdoor perimeter, lawn pests | Indoor use on smooth surfaces (rolls away); vertical surfaces | Easy application; rain-activated; lawn pest control |
| Aerosol (can) | Flying insects, quick knockdown, flushing for inspection | Long-term control; large areas (expensive); around flames | Instant kill; reaches flying targets; convenient |
| Foam | Wall voids, nests in cavities, pipe penetrations | Exposed surfaces; outdoor use in wind | Expands to fill voids; visual confirmation of coverage |
| Wettable powder/granule (WP/WDG) | Professional applications, tank mix, suspension sprays | Homeowners without proper equipment | Higher residual than EC formulations; less phytotoxicity |
The most common mistake: Using aerosol spray cans for ants and cockroaches. Repellent aerosol sprays scatter colonies, push pests deeper into walls, and can cause budding in ant species. The correct approach for ants and roaches is GEL BAIT - applied in small dots in cracks and crevices. The colony eliminates itself.
Dust application rule: Less is more. If you can see piles or lines of dust, you have applied far too much. Insects will walk AROUND visible dust deposits. A barely visible film, applied with a hand duster or puff bottle, is ideal. Think talcum powder after a shower, not flour on a cutting board.
Liquid mixing tip: Always add the product to water, not water to product. This prevents concentrated chemical from splashing. Use the measuring cup that comes with the product - kitchen measuring tools get contaminated and should never be used for food again.
Bait placement strategy: Place gel bait in small pea-sized dots (not lines or globs) in cracks, corners, hinges, and behind appliances. More dots in more locations beats fewer larger dots. Refresh bait every 2-4 weeks or when consumed. Never spray near bait stations - the repellent chemical deters pests from feeding on the bait.