Starbar
Pre-Strike Mosquito Torpedo
Larvicide · EPA-registered biopesticide
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Pros
- Kills 90–100% of larvae in the water you treat, before they can bite
- Target-specific — safe for fish, pets, birds, bees, and wildlife
- EPA-registered biopesticide
Cons
- Source control only — it lowers the future mosquito population, it does not stop tonight's bites
- Works only where you can reach standing water, and needs replacing about every 30 days
- Active ingredient concentration is not disclosed
The full review
Floating torpedo-shaped larvicide from Starbar that you place in standing water to stop mosquito larvae from becoming biting adults. Its active is S-methoprene, an insect growth regulator, which works differently from the Bti in mosquito dunks: rather than killing larvae outright, it blocks them from maturing, so treated larvae never emerge as flying, biting adults. Because of that mechanism you may still see wrigglers in the water for a while even though the treatment is working. Each torpedo treats up to 100 square feet of surface water and keeps working for up to 60 days, a longer stretch than a Bti dunk, which makes it useful for water you want to hold under control for the season. This is source control for standing water, not a repellent for your skin or a spray for the air. S-methoprene has low toxicity to people, pets, birds, and fish, though it is somewhat less target-specific than Bti because it can affect the development of some other aquatic invertebrates.
Scorecard
Expand any pillar to see exactly why it scored what it did.
Effectiveness45%85Source control: it kills roughly 90–100% of mosquito larvae in the standing water you treat, over about 100 sq ft of water per unit. It stops larvae before they become biting adults, lowering the local population over time. Because it only works where you can treat standing water and does not stop bites from mosquitoes bred elsewhere, it is scored on its larval-control efficacy, lightly discounted as a population tool rather than personal protection (reasonable confidence).
Source control: it kills roughly 90–100% of mosquito larvae in the standing water you treat, over about 100 sq ft of water per unit. It stops larvae before they become biting adults, lowering the local population over time. Because it only works where you can treat standing water and does not stop bites from mosquitoes bred elsewhere, it is scored on its larval-control efficacy, lightly discounted as a population tool rather than personal protection (reasonable confidence).
Evidence & honest claims25%29No published studies in our library directly support this product's active ingredients at their concentrations (base 20). Of 3 marketing claims audited: 2 strong, 1 moderate, 0 weak, 0 unsupported (+9).
No published studies in our library directly support this product's active ingredients at their concentrations (base 20). Of 3 marketing claims audited: 2 strong, 1 moderate, 0 weak, 0 unsupported (+9).
Safety15%84This is a biological larvicide. Its active (Bti) targets only mosquito, black fly, and fungus gnat larvae and is documented safe for fish, pets, birds, bees, and other wildlife by the EPA, WHO, and CDC. It is designed to be placed directly in standing water, so there is no dermal exposure and negligible non-target hazard. A non-Bti active here carries some aquatic caution.
This is a biological larvicide. Its active (Bti) targets only mosquito, black fly, and fungus gnat larvae and is documented safe for fish, pets, birds, bees, and other wildlife by the EPA, WHO, and CDC. It is designed to be placed directly in standing water, so there is no dermal exposure and negligible non-target hazard. A non-Bti active here carries some aquatic caution.
Transparency15%20This product publishes an ingredient list (+20); discloses 0% of active concentrations (+0); discloses 0% of all ingredient concentrations (+0); inert ingredients are not fully accounted for (0).
This product publishes an ingredient list (+20); discloses 0% of active concentrations (+0); discloses 0% of all ingredient concentrations (+0); inert ingredients are not fully accounted for (0).
Every pillar is scored from published rules. Read how we score.
Larval control
This is a larvicide: it kills mosquito larvae in the standing water you treat, stopping them before they become biting adults. It lowers the local population over time but does not stop bites from mosquitoes bred elsewhere.
Mosquitoes
EstimatedHigh- Treated water
- ~100 sq ft of water
- Larvae killed
- 90–100%
The band shown is larval control, specifically prevention of adult emergence, not personal bite protection. S-methoprene is an insect growth regulator, so it does not kill larvae on contact the way Bti does; instead it stops them from maturing, and treated larvae fail to emerge as biting adults. That means wrigglers can remain visible for a time even though the treatment is working. Each torpedo covers up to 100 square feet and lasts up to 60 days, longer than a Bti dunk, which is its main advantage. As source control it lowers the next generation of mosquitoes from the treated water but does nothing for water you do not treat or for adults flying in from elsewhere. Its non-target toxicity to people, pets, birds, and fish is low, though as a growth regulator it is a bit less target-specific than Bti and can affect the development of some other aquatic invertebrates.
Ingredient disclosure
This product publishes an ingredient list (+20); discloses 0% of active concentrations (+0); discloses 0% of all ingredient concentrations (+0); inert ingredients are not fully accounted for (0).
Only active ingredients are disclosed. The full ingredient list (inerts/carriers) is not published, so this may not be the complete formula.
Active ingredient concentrations are not published for this product.
- S-methopreneActive
Active larvicide · concentration not disclosed
Claims audit
What the marketing says, versus what the evidence supports.
“Prevents mosquito larvae from developing into biting adults”
EfficacyStrongAccurate description of how S-methoprene works. As a growth regulator it blocks maturation rather than killing larvae outright, so treated larvae do not emerge as biting adults.
“Each torpedo treats up to 100 sq ft and lasts up to 60 days”
DurationModerateMatches the label. The up-to-60-days figure is a best case under typical conditions; real duration varies with water turnover and refills, but the longer control window versus a Bti dunk is genuine.
“Won't harm people, pets, fish, birds or plants when used as directed”
SafetyStrongSupported. S-methoprene has low toxicity to mammals, birds, and fish. One caveat: as a growth regulator it is less target-specific than Bti and can affect the development of some non-target aquatic invertebrates at higher exposures, so follow label rates.
Safe around dogs & cats?
Worst case from this product’s active ingredients. Do not apply this or any human repellent to your pet.
Not veterinary advice. Full guide to repellents around pets →