Clarke
Natular DT Mosquito Larvicide Tablets
Larvicide · EPA-registered pesticide
Pros
- Kills 80-100% of larvae in the water you treat, before they can bite
- Target-specific, safe for fish, pets, birds, bees, and wildlife
- EPA-registered biopesticide
- Active ingredient concentration disclosed
Cons
- Source control only, so it lowers the future mosquito population rather than stopping tonight's bites
- Works only where you can reach standing water, and needs replacing about every 30 days
The full review
Reduced-risk larvicide tablet from Clarke built around spinosad, a compound derived from the soil bacterium Saccharopolyspora spinosa and the first larvicide registered under the EPA's Reduced Risk program. Each dual-release tablet disperses in the water within about a minute and kills mosquito larvae by ingestion and contact, overexciting their nervous system and paralyzing all four larval stages before they can mature into biting adults. It starts working within 24 hours and keeps controlling larvae for up to 60 days on a single tablet. Because of its reduced-risk profile it is labeled for water that contains fish and plants, including rain barrels, gutters, bird baths, and ornamental ponds. Sold as a 12-tablet pack, each tablet treats up to 25 square feet or about 50 gallons. This is source control for the standing water where mosquitoes breed, not a repellent for your skin.
Scorecard
Expand any pillar to see exactly why it scored what it did.
Effectiveness45%79Its job is to shrink your yard's mosquito population, and it does it well: it kills roughly 80-100% of the mosquito larvae in the standing water you treat, over about 25 sq ft of water per unit. It stops larvae before they become biting adults, thinning the next generation of mosquitoes around a breeding site. Scored on that larval-control efficacy, discounted only because it reaches the standing water you can find and treat and not the mosquitoes breeding elsewhere (lower confidence).
Its job is to shrink your yard's mosquito population, and it does it well: it kills roughly 80-100% of the mosquito larvae in the standing water you treat, over about 25 sq ft of water per unit. It stops larvae before they become biting adults, thinning the next generation of mosquitoes around a breeding site. Scored on that larval-control efficacy, discounted only because it reaches the standing water you can find and treat and not the mosquitoes breeding elsewhere (lower confidence).
Evidence & honest claims25%30No published studies in our library directly support this product's active ingredients at their concentrations (base 20). Of 4 marketing claims audited: 2 strong, 2 moderate, 0 weak, 0 unsupported (+10).
No published studies in our library directly support this product's active ingredients at their concentrations (base 20). Of 4 marketing claims audited: 2 strong, 2 moderate, 0 weak, 0 unsupported (+10).
Safety15%96This 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.
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.
Transparency15%85This product names its active ingredient (+30); uses a biological active whose potency is measured in living units, not a weight percent, so it is credited as fully disclosed (+35); publishes a concrete coverage figure (+20).
This product names its active ingredient (+30); uses a biological active whose potency is measured in living units, not a weight percent, so it is credited as fully disclosed (+35); publishes a concrete coverage figure (+20).
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
EstimatedModerate- Treated water
- ~25 sq ft of water
- Larvae killed
- 80-100%
The band shown reflects larval control, not personal protection. Spinosad is highly effective at killing mosquito larvae, with lab studies showing close to complete Aedes mortality at label rates, though field trials show more variable real-world control of roughly 53 to 84 percent within two weeks depending on species and site. One dual-release tablet starts killing within 24 hours and keeps controlling larvae for up to 60 days per treatment. This is source control that kills larvae in the standing water where mosquitoes breed before they mature into biting adults, so it works on your breeding sites over days and weeks rather than putting protection over your skin right now.
Ingredient disclosure
This product names its active ingredient (+30); uses a biological active whose potency is measured in living units, not a weight percent, so it is credited as fully disclosed (+35); publishes a concrete coverage figure (+20).
Only active ingredients are disclosed. The full ingredient list (inerts/carriers) is not published, so this may not be the complete formula.
- SpinosadActive
Active larvicide · 7.48%
Claims audit
What the marketing says, versus what the evidence supports.
“Begins killing larvae within 24 hours and controls mosquito larvae for up to 60 days.”
DurationModerateMatches EPA label duration; independent field trials show shorter, variable real-world control.
“Can be applied to water sites that contain fish and plants.”
SafetyStrongSupported by the reduced-risk EPA registration and spinosad's low non-target aquatic toxicity.
“Active ingredient derived from a naturally occurring soil bacterium.”
NaturalStrongFermentation origin is documented; natural does not by itself imply harmlessness.
“Controls container-breeding Aedes that can transmit Dengue, Chikungunya, and Zika.”
EfficacyModerateAedes larval control is well documented; the disease framing describes the vector, not a proven reduction in human disease.