Insect Growth Regulators (IGRs)
Pesticides that disrupt insect development and reproduction by mimicking or blocking growth hormones - providing long-term population suppression.
Detailed Overview
IGRs prevent immature insects from developing into reproducing adults by interfering with molting hormones. Two types: (1) Juvenile hormone mimics (methoprene, hydroprene, pyriproxyfen) prevent larvae from maturing - stuck in immature stage until death. (2) Chitin synthesis inhibitors (noviflumuron, lufenuron, novaluron) prevent proper exoskeleton formation during molting. IGRs do not kill adult insects already present - only prevent next generation. Slow-acting requiring 4-12 weeks to see population decline. Ideal for: fleas (prevent larvae/pupae from developing), stored product pests (prevent reproduction in food facilities), roaches (long-term population suppression), mosquitoes (larvicides prevent pupation). Often combined with adulticides for complete control - IGR prevents future generations while adulticide kills current adults. Extremely low mammalian toxicity making them ideal for sensitive accounts. Cannot develop resistance easily because affect basic physiology. Long residual (6-12 months indoors) when applied properly. Best for prevention and long-term suppression, not rapid knockdown. PCOs use IGRs as foundation of sustainable programs combined with sanitation and exclusion.
When to Use
Use for long-term population suppression in flea control programs, stored product pest management, German roach programs, and mosquito larviciding. Combine with adulticides for immediate plus long-term control.
Required Skill Level
Should only be performed by licensed pest management professionals
Benefits
- Long residual control - 6-12 months
- Prevents reproduction eliminating future generations
- Extremely low mammalian toxicity
- Ideal for sensitive accounts
- Low resistance development risk
- Works on pests resistant to conventional insecticides
Limitations
- Does not kill existing adults
- Slow-acting - 4-12 weeks for population reduction
- Must be combined with adult control for immediate results
- Expensive compared to conventional insecticides
- Only affects immature life stages
Related Concepts
Other product types that may be useful
Reduced-Risk Pesticides
Low-toxicity pesticide products that pose minimal risk to humans, pets, and the environment while remaining effective against target pests.
Non-Repellent vs Repellent Chemistry
Understanding the difference between insecticides pests cannot detect (non-repellent) versus those they avoid (repellent) - critical for colony elimination.
Desiccant Dusts
Insecticidal dusts that kill by physically abrading the waxy cuticle causing dehydration - cannot be resisted and provide permanent control if kept dry.