The label is the law. Read your product's label before you mix or apply; the rates here come from the labels listed under Sources.
- Active ingredient
- Etofenprox (CAS 80844-07-1)
- Chemical class
- Pyrethroid ether; IRAC Group 3A sodium channel modulators.[2]
- Mode of action
- IRAC Group 3A: Sodium channel modulators: pyrethrins and pyrethroids[2]
- Signal word
- Zenivex E20: Caution[1]
Fogging is the last step, not the first
Space sprays kill adult mosquitoes flying at the time of treatment. Around the home, the CDC's first steps are repellent, covering skin, screens and emptying standing water once a week.[1][3]
Where it is used
It is restricted to government vector-control officials, applicators certified for adult mosquito control, or people under their direct supervision; it isn't a homeowner product.[1]
Fogging is done when ground wind is at least 1 mph but not over 10 mph and temperatures are at least 50°F, ideally during a temperature inversion that keeps the fog near the ground, when mosquitoes are most active.[1]
Because it is a Group 3A pyrethroid, the label asks applicators to rotate to other groups and watch for survivors that suggest resistance.[1]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Zenivex E20[1] | Wellmark International | 2724-791 | 20.0% | oil-based ultra-low-volume concentrate | Caution |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Zenivex E20 | Outdoor space spray over residential, commercial, recreational and agricultural areas | Adult mosquitoes, non-biting midges, biting and nuisance flies | 0.00175–0.007 lb etofenprox per acre[1] Used undiluted or diluted with oil, never water. No more than 0.18 lb etofenprox per acre per site per year, or 25 applications per site per year, unless a health agency documents a disease threat. |
Safety and environmental hazards
People
Signal word CAUTION: causes moderate eye irritation, and repeated exposure can irritate skin. Applicators wear long sleeves, long pants, socks and shoes.[1]
Pets
The label's precautions cover people and domestic animals together: avoid contact with eyes, skin and clothing.[1]
Bees and pollinators
Highly toxic to bees exposed to direct treatment on blooming crops or weeds. Applications are timed for the longest gap before bees are active again, and not made over blooming plants while bees are foraging unless a health agency has documented a disease threat.[1]
Fish and water
Toxic to fish and aquatic invertebrates; not applied over lakes, streams, ponds or marshes except where adult mosquitoes are present and the weather will carry the spray away from the water.[1]
Common questions
- Can I buy Zenivex for my yard?
- No. The label limits use to public health and vector control officials, certified adult mosquito control applicators, and people they directly supervise.[1]
- Is etofenprox fogging harmful to bees?
- The label says it is highly toxic to bees directly exposed on blooming plants, so applications are timed away from bee activity.[1]
- How much etofenprox is sprayed per acre?
- 0.00175 to 0.007 pounds of etofenprox per acre per application, with a yearly cap of 0.18 pounds per acre.[1]
Sources
- U.S. EPA Pesticide Product Label System, “Zenivex E20 (RF2056 OL) label, EPA Reg. No. 2724-791 (EPA-stamped, Sept. 10, 2025).” www3.epa.gov/pesticides/chem_search/ppls/002724-00791-20250910.pdf (accessed 2026-10-06)
- Insecticide Resistance Action Committee, “IRAC Mode of Action Classification Scheme, Version 11.5 (Feb. 2026).” irac-online.org/documents/moa-classification/ (accessed 2026-10-06)
- U.S. Centers for Disease Control and Prevention, “Preventing Mosquito Bites.” www.cdc.gov/mosquitoes/prevention/index.html (accessed 2026-10-06)