🧪 Active Ingredient Profile
Methoprene (Precor) — IGR for Flea & Stored Product Control
Insect Growth Regulator (Juvenile Hormone Analog) · CAS 40596-69-8
Methoprene is an insect growth regulator (IGR) that prevents flea larvae from maturing to the adult stage. It's one of the safest and most important tools in flea management — and equally valuable for stored product pest programs.
Mode of Action
Mimics juvenile hormone — prevents larvae from completing development to the adult stage; no direct toxicity to adults
🦺 Personal Protective Equipment (PPE)
Required PPE varies by formulation and application method. Always read the product
label — the label is the law and overrides general guidance.
- Standard gloves
- Low toxicity — minimal PPE required
- Safe around mammals — targets only juvenile insect hormones
⚠️ Label compliance: The product label is a legal document under FIFRA.
Applying any pesticide in a manner inconsistent with its label is a federal violation.
📋 Application Best Practices
- Read the full label before each use — formulations change and label requirements may differ from previous products you've used.
- Apply at the right rate — more is not more effective. Over-application wastes product, creates unnecessary exposure, and is illegal.
- Target harborage and entry points, not just visible pest activity. Treating where pests hide is more effective than treating where you see them.
- Record the application — note the product, rate, area treated, and date. Required for commercial applications; best practice for homeowners.
- Ventilate the treatment area after application and before re-entry.
💡 Storage: Store in original container, away from children, in a cool dry location. Never transfer to food or beverage containers. Check local regulations for disposal — most areas have household hazardous waste collection events.
❓ Frequently Asked Questions
Q: Is methoprene safe for pets?
Follow the product label. Keep pets out of treated areas until completely dried (2–4 hours for sprays). Once dry, treated surfaces pose minimal risk to dogs and cats.
Q: Can I use methoprene indoors?
Check the specific product label — formulations vary. Baits and dusts often have indoor labeling; concentrates and granulars are typically outdoor.
Q: How long does methoprene last after application?
Residual varies by formulation, surface type, weather, and UV exposure. Indoor applications last longer than outdoor. Check the product label for re-application intervals.
Q: What should I do if exposed?
Remove contaminated clothing, wash skin with soap and water. For eye contact, rinse 15–20 minutes. For ingestion or severe symptoms, call Poison Control (1-800-222-1222). Have the product label available.
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Reviewed by Derek GiordanoContent reviewed by a licensed pest management professional and cross-referenced against EPA, university extension, and manufacturer technical data. Last reviewed: April 2026.
