How Mosquito Bits Work
Mosquito Bits are corn-cob granules coated with BTI (Bacillus thuringiensis subspecies israelensis) — a soil bacterium discovered in 1976 that specifically targets the digestive systems of mosquito and black fly larvae. The corn-cob granules float briefly when sprinkled onto water, then sink as they absorb moisture. As the bits dissolve, they release BTI proteins into the water column where larvae filter-feed.
BTI is one of the most species-specific insecticides ever developed. It only affects mosquito larvae, black fly larvae, and a few related midge species. Humans, pets, fish, frogs, dragonflies, water beetles, beneficial insects, pollinators, and birds are completely unaffected. Health Canada has approved BTI for residential use, and some provinces approve it for drinking water reservoirs.
When to Use Bits Instead of Dunks
- You found larvae unexpectedly — wriggling in a saucer, an old bucket, a clogged gutter — sprinkle bits for 30-minute knockdown
- Small water sources — bird baths, kiddie pools, plant saucers — where a floating dunk tablet would be visually awkward
- Pet water bowls left outside — sprinkle a tiny pinch (BTI is safe; the bits are essentially corn-cob anyway)
- Drainage trays under outdoor planters
- Tarp-covered boats with rainwater pooled on top
- Septic tank ventilation pipes that can hold water
- Storm drain catch basins on your property
When Dunks Are Better
- Rain barrels — drop one dunk per 50 gallons, replace monthly
- Decorative ponds with fish — slow-release lasts the season, fish unaffected
- Neglected swimming pools with accumulated rainwater
- Drainage ditches that hold water for weeks
- Tree holes and stump cavities
- Any standing water you can’t check on weekly
The Smart Approach: Use Both
Most Canadian homeowners with mosquito issues end up using BOTH. The dunk goes in the rain barrel for set-and-forget protection — drop it in May, forget about it until June. The bits container sits in the garden shed for emergency use whenever you discover larvae somewhere unexpected.
For a typical GTA backyard with one rain barrel and a few potential standing-water spots, your annual BTI budget is roughly $30: one 6-pack of dunks ($15) covers the rain barrel for the full May–September season, and one 8-oz container of bits ($15–$22) handles every other standing-water situation that comes up.
Bits + Barrier Spray: The Complete Mosquito Strategy
BTI bits and dunks solve the LARVAL side of mosquito control — but they only work on water you actually treat. Adult mosquitoes flying in from neighbours’ yards, ravines, and creeks are unaffected. For complete protection in your GTA backyard:
- BTI bits/dunks in any standing water on your property ($30/season)
- Habitat modification — drain anything you can drain, mow short, clear leaf litter
- Professional barrier spray — BuzzSkito’s seasonal program targets adult mosquitoes flying onto your property, with Health Canada-approved residual formula that lasts 21–30 days per treatment