Knockdown vs Residual
Understanding the difference between fast-acting contact insecticides for immediate kill and long-lasting residual products for ongoing protection.
Detailed Overview
Knockdown products kill quickly on contact (pyrethrins, aerosols) - use for immediate visible results, flushing pests from harborage, or customer satisfaction when live pests visible. Knockdown is temporary - dead bugs now, but no protection tomorrow. Residual products persist for weeks or months after application (microencapsulated formulations, non-repellents, dusts) - slower kill but continues working long after application. Most professional treatments use residuals for ongoing control. Some products combine both: pyrethrins for knockdown + permethrin for residual. Know when to use each: Knockdown appropriate for: severe visible infestations where customer expects to see immediate results, flushing applications to force bugs from voids for counting/identification, restaurants where dead bugs demonstrate service. Residual appropriate for: ongoing pest prevention, crack-and-crevice treatments in voids, perimeter barriers, void injections, situations where customer will not see immediate results but long-term control needed. Many PCO callbacks result from using only knockdown without residual protection. Professional approach: combine both - initial knockdown for cleanout, then residual for prevention.
When to Use
Use knockdown for initial cleanout when live pests visible and customer expects immediate results. Follow with residual treatments for long-term control. Use residual alone for prevention programs.
Required Skill Level
Requires some training and experience in pest management
Benefits
- Knockdown provides immediate customer satisfaction
- Residual provides long-term protection
- Combining both delivers results plus prevention
- Appropriate product selection reduces callbacks
- Residuals reduce service frequency
Limitations
- Knockdown alone leads to callbacks - temporary fix
- Residual alone may not satisfy customer wanting immediate results
- Must balance both for comprehensive programs
- Environmental conditions affect residual longevity
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.