Mode of Action (MoA)
Understanding how pesticides kill pests at the molecular level - critical for product selection and resistance management.
Detailed Overview
Mode of Action describes the biochemical process by which an insecticide kills. Pyrethroids and neonicotinoids both attack the nervous system but at different sites - pyrethroids affect sodium channels, neonicotinoids affect nicotinic receptors. IGRs disrupt molting hormones. Desiccants physically damage the waxy cuticle causing dehydration. Anticoagulants prevent blood clotting in rodents. MoA determines speed of kill: pyrethrins provide quick knockdown; fipronil acts slowly allowing transfer to colony; IGRs take weeks showing effects. MoA affects application strategy: stomach poisons (baits) require ingestion; contact insecticides work through cuticle contact; fumigants penetrate as gas. Understanding MoA is critical for resistance management - IRAC (Insecticide Resistance Action Committee) assigns MoA group numbers to products. Rotating between different MoA groups prevents resistance development. Using two products with same MoA does not prevent resistance even if different active ingredients. PCOs should know MoA groups for their core products and rotate annually.
When to Use
Consider MoA when selecting products for treatment programs. Rotate MoA groups seasonally or annually to prevent resistance. Check product labels for IRAC MoA group numbers.
Required Skill Level
Should only be performed by licensed pest management professionals
Benefits
- Enables effective resistance management programs
- Improves product selection for specific situations
- Explains why some products work faster than others
- Allows strategic rotation to extend product effectiveness
- Helps troubleshoot treatment failures
Limitations
- Requires learning MoA classifications
- Limited product choices in some MoA groups
- Must track which MoA groups used at each account
- Some products have multiple MoAs complicating rotation
Related Concepts
Other principles that may be useful
Integrated Pest Management (IPM)
A prevention-based pest management method that provides long-lasting pest control, improves building conditions, and is less harmful to residents and pets than traditional pest control.
Pest Triangle
The four essential requirements pests need to survive: food, water, shelter, and ways to get around. Eliminating any of these makes an environment inhospitable to pests.
Threshold Levels
The point at which pest populations or damage reaches a level that requires action. IPM uses threshold levels to determine when treatment is necessary rather than treating on a schedule.